Water Changes

[afriend]

What is the purpose of making very large water changes? My water has the following characteristics: Am=0, Ni=0, Ph=7.2, Na= 5 or less. My aquarium is a show tank, so I'm not trying to raise young discus. I want my adult discus to remain healthy and happy. So, if I make enough water changes to maintain the nitrate (Na) at 5ppm or less, what advantage (if any) is there in making additional water changes? Right now I change about 75% of the water weekly. What weekly water change % would you recommend for my tank, and why?

[afriend]

I really was hoping for some response to my question above. Maybe I didn't provide enough information. My tank is 75 g and I have 6 adult discus in it. I presently make about a 75% change weekly (the exchange occurs gradually with small changes daily such that the total weekly exchange is about 75%) This is accomplished with an automated exchange system. I can easily change the amount by reprograming the timer that controls the pump.

I feed my fish frozen blood worms, frozen California black worms, and tetra color bits.

My question is, why make more water exchange than is necessary to keep the nitrate less than 5ppm?

For those of you out there that know alot more than I do, I would really appreciate your inputs.

[Altum Nut]

I think more information is required.
How long has this set-up been running?
Is it a bare bottom tank?
Are you adding aged water or straight tap?
IMO your testing frequently which is great. No other suggestions can be offered unless the above questions are determined.
If you would like to add a pic with your reply.

...Ralph

[Skip]

afriend
i believe it just keeps the water fresh as possible.. your probably better off doing one large change per week.. that way the water is really fresh..!! thats what i do.. i like to get 2-3 wc in my 75 per week for my young adults.. also have 4 hydro 5 sponges in there with AC 110

[afriend]

I think more information is required.
How long has this set-up been running?
Is it a bare bottom tank?
Are you adding aged water or straight tap?
IMO your testing frequently which is great. No other suggestions can be offered unless the above questions are determined.
If you would like to add a pic with your reply.

...Ralph

The tank has been up an running for more than 3 years.
Bare bottom.
My water source is from my own well, 500 feet deep.
The water is aged more than a week.
I mix RO water with 20% straight well water. PH 7.2
KH less than 50 ppm, GH less than 20 ppm.

Would like to provide a picture, but my wife has my camera with her on a trip and won't be back for a week.

Thank you for your consideration. If I can provide any other information, please ask.

Paul

[afriend]

afriend
i believe it just keeps the water fresh as possible.. your probably better off doing one large change per week.. that way the water is really fresh..!! thats what i do.. i like to get 2-3 wc in my 75 per week for my young adults.. also have 4 hydro 5 sponges in there with AC 110

Well, my question is, what is it about "fresh" water that makes it better? That is, what parameter makes it fresh and how does one measure it? I understand the nitrification cycle and know why nitrate builds up in the water and that water changes reduce nitrate level. Also, my understanding is that nitrate can be harmful it it exceeds some level much greater than 5 ppm. But, I make suffient water changes to maintain nitrate levels much below 5 ppm. So what other parameter other than nitrate needs to be maintained?

Paul

[Skip]

Well, my question is, what is it about "fresh" water that makes it better? That is, what parameter makes it fresh and how does one measure it? I understand the nitrification cycle and know why nitrate builds up in the water and that water changes reduce nitrate level. Also, my understanding is that nitrate can be harmful it it exceeds some level much greater than 5 ppm. But, I make suffient water changes to maintain nitrate levels much below 5 ppm. So what other parameter other than nitrate needs to be maintained?

Paul

Paul..

i don't have answer you want..

good luck :)

[ericatdallas]

Well, my question is, what is it about "fresh" water that makes it better? That is, what parameter makes it fresh and how does one measure it? I understand the nitrification cycle and know why nitrate builds up in the water and that water changes reduce nitrate level. Also, my understanding is that nitrate can be harmful it it exceeds some level much greater than 5 ppm. But, I make suffient water changes to maintain nitrate levels much below 5 ppm. So what other parameter other than nitrate needs to be maintained?

Paul

Disclaimer: I'm stating some facts but I'm not drawing conclusions or inferring anything from it until I do (I'll let you know when).

First, other compounds build up in water other than nitrates. For instance, our air is filled with contaminants. The food we feed our fish often times have heavy metals and other contaminants. So while your nitrates may be low (from plants), it could still have other harmful and growth limiting compounds. What those are would be mere speculation. When I got into Discus keeping I searched for it, but haven't found a good answer for me either.

Speculation time: There are also dissolved organics (fish excrete other types of waste as well) that might hinder growth.

So why so much attention on nitrates (okay, this is just my speculation). It's because nitrates are easy and cheap to measure. They're also symptomatic of dirty water and there's probably also a correlation with nitrates and 'other' compounds that limit growth.

Let me use an analogy (and hopefully it's clear). If you're having trouble breathing one night and someone tells you,it's because the oxygen supply is limited in your room so they hand you an oxygen tank. You breathe and go back to sleep. You never wake up...

Because you died in the fire.

See, lack of oxygen was just a symptom or one problem. Sometimes there are other hazards that go with it, but they're related.

[Sean Buehrle]

Disclaimer: I'm stating some facts but I'm not drawing conclusions or inferring anything from it until I do (I'll let you know when).

First, other compounds build up in water other than nitrates. For instance, our air is filled with contaminants. The food we feed our fish often times have heavy metals and other contaminants. So while your nitrates may be low (from plants), it could still have other harmful and growth limiting compounds. What those are would be mere speculation. When I got into Discus keeping I searched for it, but haven't found a good answer for me either.

Speculation time: There are also dissolved organics (fish excrete other types of waste as well) that might hinder growth.

So why so much attention on nitrates (okay, this is just my speculation). It's because nitrates are easy and cheap to measure. They're also symptomatic of dirty water and there's probably also a correlation with nitrates and 'other' compounds that limit growth.

Let me use an analogy (and hopefully it's clear). If you're having trouble breathing one night and someone tells you,it's because the oxygen supply is limited in your room so they hand you an oxygen tank. You breathe and go back to sleep. You never wake up...

Because you died in the fire.

See, lack of oxygen was just a symptom or one problem. Sometimes there are other hazards that go with it, but they're related.

Good one!

[lipadj46]

On one hand I think in your case if weekly water changes are keeping you nitrates low enough and your fish healthy then stick with what is working. But on the other hand if you have essentially free water and an auto change system why not up the % to say 200% per week? I see no downside and the upside is you will have cleaner water.

[plecocicho]

wc regime = stockxfiltrationxfoodxagexwater
stock-more fish you have, sooner your waters get dirty
filtration-larger filters (sump, internal compartment filters, canisters)can take care of biggerbioloads
food-mixes make your water dirty quick
age-smaller fish need more food and cleaner water
water-when you source water has high nitrates you need to change more

so best case scenario:
understock tank with adult fish, large canister filter and/or internal /external of 20% tank volume, feding with either live food, flakes or fozen food (artemia, nidge larvae) and greta source water means less water change
worst case scenario(typical grow out tank):
overstocked or near with small fish, who are feed many times with messy foods(bh mix), filtration comprimising only of a small air driven sponge filter means huge bioload and a lot of wc.
Of course larger wc are better, but if you consider the above equation, you can do smaller wc and maintain cleaner water. tahat doesnt mean that wc then become obsolete.

[Altum Nut]

On one hand I think in your case if weekly water changes are keeping you nitrates low enough and your fish healthy then stick with what is working. But on the other hand if you have essentially free water and an auto change system why not up the % to say 200% per week? I see no downside and the upside is you will have cleaner water.

Hey Paul,

I would have to agree with the above. I wish i really had a technical solution to your original question.
The w/c rule was not written in stone however a fair number of Discus newbie's start off on the right track but become laid back when testing is required...before you know it their posting in the disease section.
I do not test myself which is why i never take chances. I do 90+% w/c per day when growing out and 3x50% w/c per week with my Adults.
In closing I really think you on the ball and if it's working for you then let it be.
Would still like to see pictures when your wife get's back.

...Ralph

[afriend]

Thanks all for all of your very excellent replies. I especially appreciate Warlock's honesty in his reply "I don't have the answer you wan't. Well, I don't have the answer either, but I'm begining to suspect that it is due to all the organic material added to the water (fish waste, food not eaten etc). I suspect this due to the number of replies inferring this. The nitrification process begins with ammonia which is produced by fish and rotting organic material and ends with nitrate. But I'm reasonably sure that ammonia is not the only product produced by organic material, and perhaps these other products are produced in larger quantities other than nitrate. Thus additional water changes reduce these other products to acceptable levels.

Do any of you know if there is a test available for measuring the amount of organic material in an aquarium?

Thanks again to each and every one that took the time to reply. Your inputs are truly appreciated.

[afriend]

Hey Paul,

I would have to agree with the above. I wish i really had a technical solution to your original question.
The w/c rule was not written in stone however a fair number of Discus newbie's start off on the right track but become laid back when testing is required...before you know it their posting in the disease section.
I do not test myself which is why i never take chances. I do 90+% w/c per day when growing out and 3x50% w/c per week with my Adults.
In closing I really think you on the ball and if it's working for you then let it be.
Would still like to see pictures when your wife get's back.

...Ralph

I'm going to increase my water changes immediately to 50% daily. I like to test because I'm a retired engineer and have the time to do it and enjoy anything scientific. If I can understand it, I've learned that there is a much better chance of obtaining the results that I want. My discus bring a lot of joy for me and I want to care for them in the best way I can. Will post some pictures after my wife returns with my camera.

[judy]

there is a Total Dissolved Solids meter you can buy-- a TDS meter. That would provide some additional indication of water quality. I have one I use about once a month. I vaguely recall the TDS should read less than 200, but that the lower the better.

[Northwoods Discus]

Bacteria and parasite buildup. Depletion of essential minerals. Trace minerals depleting or like Eric said build up of possible other toxic materials. These are some other possibilities.

[ericatdallas]

Judy, TDS meter could be misleading as well... especially in a planted tank. While DOCs might increase TDS, plants might lower it as well by nutrient absorpotion. So my tap water is 350ppm, but it may lower due to nutrient absorption from a plant but other toxins might increase but never surpass the 350ppm baseline.

Obviously, there's no magic equation to calculate this since there are so many variables and it would take a very controlled tank to even get close to making a projection.

I did see an article in a journal yesterday discussing a recirculating system comparing WC levels. There is a correlation between 'near-zero' water exchange and 'high' water exchange with survival rate and development dependent on volume exchange.

The author concluded that a number of factors could come to play. The leading ones was nitrates, but phosphours was up there too... so testing for phosphorous might be a good idea if you want to limit your WC.

I'll see if I can find it. I have a deadline right now, but when I quickly searched for it, Aquacultural Engineering in the past couple months has released a lot of articles on RAS (recirculating agricultural systems aka aquaponics) that I'll read through. Typically, RAS systems target higher nitrate levels with some 'philosophies' claiming that 'near-zero' water exchange is necessary for fish and plants. Lately, research has shown (not surprisingly) that even if nitrates remain relatively low and in target range, that fish are healthier w/ high exchange rates.

Trust me, the above is like talking to a door nob and pulling your own teeth when discussing this with aquaponics hobbyists. They ignore the latest research, claim salt is the way to fix all fish diseases, and scoff at anyone that claims 200+ppm nitrates is unhealthy (I am not exaggerating on that).

[afriend]

there is a Total Dissolved Solids meter you can buy-- a TDS meter. That would provide some additional indication of water quality. I have one I use about once a month. I vaguely recall the TDS should read less than 200, but that the lower the better.

Judy,

Thanks. Fish waste and rotting food undoubtably increase increase disolved solids in the water. Think I'll get one of them and use it so that I can learn more about it. Wonder what the TDS is in my tanks. Good info, thanks again.

[afriend]

Judy, TDS meter could be misleading as well... especially in a planted tank. While DOCs might increase TDS, plants might lower it as well by nutrient absorpotion. So my tap water is 350ppm, but it may lower due to nutrient absorption from a plant but other toxins might increase but never surpass the 350ppm baseline.

Obviously, there's no magic equation to calculate this since there are so many variables and it would take a very controlled tank to even get close to making a projection.

I did see an article in a journal yesterday discussing a recirculating system comparing WC levels. There is a correlation between 'near-zero' water exchange and 'high' water exchange with survival rate and development dependent on volume exchange.

The author concluded that a number of factors could come to play. The leading ones was nitrates, but phosphours was up there too... so testing for phosphorous might be a good idea if you want to limit your WC.

I'll see if I can find it. I have a deadline right now, but when I quickly searched for it, Aquacultural Engineering in the past couple months has released a lot of articles on RAS (recirculating agricultural systems aka aquaponics) that I'll read through. Typically, RAS systems target higher nitrate levels with some 'philosophies' claiming that 'near-zero' water exchange is necessary for fish and plants. Lately, research has shown (not surprisingly) that even if nitrates remain relatively low and in target range, that fish are healthier w/ high exchange rates.

Trust me, the above is like talking to a door nob and pulling your own teeth when discussing this with aquaponics hobbyists. They ignore the latest research, claim salt is the way to fix all fish diseases, and scoff at anyone that claims 200+ppm nitrates is unhealthy (I am not exaggerating on that).

Eric,

I don't have a planted tank, so that is really not a factor for me. Also, I'm really not trying to limit water changes, just trying to get a handle on knowing how much water change is necessary. Can you please tell me what DOCs are? I'm guessing that it means disolved organic compounds (please don't laugh too hard if I guessed wrong). Also, what daily percentage of water exchange would you recommend for my tank?

Paul

[ericatdallas]

You're right, dissolved organic compounds.

Click here for additional abbreviations and acronyms :) (http://forum.simplydiscus.com/showthread.php?88079-Discus-and-Aquarium-Abbreviations&p=822764#post822764)

Paul, I think you should do the maximum you're comfortable doing with respect to your abiity, time commitments, budget, and experience. The ideal situation is your fish gets mountain fresh water warmed to an ideal Discus temp continuously flowing through their tank. Heck, the ideal situation is throwing them in a continous flowing source of water... maybe waterways in and around the Amazon River is a good candidate? ;)

[Skip]

Paul.. 50% once a week.. More times if they are acting funny someday.. Its not rocket science.. u will figure it out...

[afriend]

Eric, Warlock

I hope you will forgive me if it appears that I'm making too much of this. But you see, I'm just an old retired engineer who likes to make sense of things. I've done a little searching on the internet about this subject today, and I'm pretty sure that the answer lies in the amount of organic material in the water (from fish poop and food). I'm going to purchase a TDS meter which indicates the total amount of disolved solids in the water (it measures both organic and inorganic). I can get a handle on the amount of inorganic solids by measuring the water before it goes into the tank. My source of water is from a deep well so I'm pretty sure it does not contain organic solids). I'm assuming that the only other significant source of substances introduced into the tank occurs when feeding the fish (it seems to me that anything else would be quite small). Thus, any increase in TDS would be attributed to fish poop and food. Please feel free to jump in and offer suggestions whenever you want. Maybe I can learn something.

I agree, the best place for my discus is the Amazon River. Problem is, it makes for a long trip to see them.

[Skip]

AF..

i do my water changes straight from tap.. with a python hooked up at the faucet.. i do about 2/3 water change.. or to where ever my heater is.. (i just have then laying/hanging at the bottom..

at times.. it think going more then 50% can be a little much for them.. but i only have sponges in a couple of tanks and the water is not as clear without mechanical filtration..

not everybodys water is the same.. nor are peoples fish they same..

one tank will tank a wc with no problem.. another tank in your house done the same exact way.. will upset them and they will not be happy for a couple of hours..

thats what i mean by you will figure it out.. 50% is a good amount to shoot for.. its the people that do 10% every 3 weeks on a 125g.. then can get into trouble somewhere down the line..

cleaner/freshwater is best for the fish..

ps.. are you going straight from tap.. or age..?

[afriend]

Eric, Warlock:

I learned today that DOCs reduce the amount of oxygen in the water. Since elevated temperatures also reduce oxygen, it seems to me that one would want to keep DOCs within acceptable limits. Another reason to reduce DOCs is to slow the growth of algae.

[ericatdallas]

What kind of engineer are you? Not that it matters, just curious because several of SD members are engineers as well. Warlock is a Civil Engineer, Pat is a software engineer, Chad Hughes in an aerospace engineer and I'm an Electrical Engineer/Physicist-in-training.

Another source of contamination (it can vary in significance) is the air. If you don't believe me run your hand across the top of your refrigerator. If your hand is clean, then ask your wife how much dirt she finds :)

[afriend]

What kind of engineer are you? Not that it matters, just curious because several of SD members are engineers as well. Warlock is a Civil Engineer, Pat is a software engineer, Chad Hughes in an aerospace engineer and I'm an Electrical Engineer/Physicist-in-training.

Another source of contamination (it can vary in significance) is the air. If you don't believe me run your hand across the top of your refrigerator. If your hand is clean, then ask your wife how much dirt she finds :)

Eric,

I always enjoy meeting engineers. If you are in training, does that mean that you are presently in school? I have a degree in Electrical Engineering as well a degree in Aeronautical Engineering. My speciality was Guidance, Navigation, and Control of spacecraft. In my first job out of college I helped put the first men on the moon as part of the Apollo Program.

Getting back to water issues. I agree with you that contaminants will enter the water thru the air. Maybe I could be wrong, but my guess is that this source is small compared to the amount of food that goes in day after day. Also, I suspect that rotting organic materal will produce all sorts of harmful compounds, not to mention the parasites and bacteria that will feed on it. Anyhow, this is just a guess on my part, and I've been known to have made a mistake or two (maybe more) in my life.

Thanks for your input. I plan to study this question a little more and will think about it more.

Hey, I just thought of something else. Parasites and bacteria can enter thru the air. If they find an abundance of food (rotting organic material) then there is probably a greater chance that they can develop into a problem.

[ericatdallas]

Eric,

I always enjoy meeting engineers. If you are in training, does that mean that you are presently in school?

I have a B.S. and M.S. in Electrical Engineering and I'm currently getting a PhD in Physics. So, yes, I'm currently in school.



I have a degree in Electrical Engineering as well a degree in Aeronautical Engineering. My speciality was Guidance, Navigation, and Control of spacecraft. In my first job out of college I helped put the first men on the moon as part of the Apollo Program.

Okay, I'm jealous. That's what I want to do "when I grow up". In fact, part of the reason why I am getting my PhD is to direct my skills for space electronics research.



Getting back to water issues. I agree with you that contaminants will enter the water thru the air. Maybe I could be wrong, but my guess is that this source is small compared to the amount of food that goes in day after day. Also, I suspect that rotting organic materal will produce all sorts of harmful compounds, not to mention the parasites and bacteria that will feed on it. Anyhow, this is just a guess on my part, and I've been known to have made a mistake or two (maybe more) in my life.

No, your right, it's probably small, but I guess that also depends on your bioload and air quality :) I can remember places where I had to wipe the dust off my desk daily. Some places in New Mexico and Arizona come to mind.






Hey, I just thought of something else. Parasites and bacteria can enter thru the air. If they find an abundance of food (rotting organic material) then there is probably a greater chance that they can develop into a problem.

I suppose... I'm not too familiar with this, but I'm thinking while possible, it's not likely because terrestrial bacteria and parasites aren't necessarily a problem for aquatic life and vice versa. Though there are some that are...

[shoveltrash]

http://cosgan.de/images/midi/froehlich/a040.gif http://cosgan.de/images/midi/froehlich/a040.gif http://cosgan.de/images/midi/froehlich/a040.gif
I just wanted to say, what an excellent discussion! I'm no engineer (just an old surgical nurse), and am frankly in awe of members here......typically I have nothing to contribute, being a 'newbie.' However I can't help but post in appreciation of this forum and the information to be found here (this thread is a perfect example).
so, er, thanks :D

[Sean Buehrle]

Judy,

Thanks. Fish waste and rotting food undoubtably increase increase disolved solids in the water. Think I'll get one of them and use it so that I can learn more about it. Wonder what the TDS is in my tanks. Good info, thanks again.

You should do some research on what a Tds meter measures and how it measures.
It won't measure all organic compounds, fish waste and such.

Using a Tds meter to tell you when to do a water change is like using a telescope to look at a molecule.

Randy farley has some good info on Tds meters, look his name up and read his info.

[jimg]

speciality was Guidance, Navigation, and Control of spacecraft. In my first job out of college I helped put the first men on the moon as part of the Apollo Program.
funny thing reading this, my uncle is about your age an electrical engineer and worked on the ground tracking electronics for one of the first Apollo's. he lived in nj and worked in manhattan

[afriend]

ything=Sean Buehrle;824372]You should do some research on what a Tds meter measures and how it measures.
It won't measure all organic compounds, fish waste and such.

Using a Tds meter to tell you when to do a water change is like using a telescope to look at a molecule.

Randy farley has some good info on Tds meters, look his name up and read his info.[/QUOTE]

Sean,

I don't want to present myself as knowing much about the subject of TDS. However, I did as you suggested and looked up Randy Farley's work. He is involved almost entirely with reefs and salt water. The use of a TDS meter in salt water is quite a bit different due to the large amount of salt. (Thats what I got after reading Farley and others on the subject.)

There's a well written input on the plecoplanet forum titled "The Importance of TDS in the Freshwater Aquarium" by Niels Jensen. A quotation from his article is as follows:

TDS considerations : Water Changes
I now also regard TDS levels as a means of deciding on when to do a water change. A rise in TDS levels means I need to change some water and thereby lower TDS levels. Rapidly increasing TDS levels can also indicate over-feeding, an over-stocked tank, or general bad maintenance.

In any case, I purchased a TDS meter and intend to experiment with it to see if I can learn anything interesting. Won't get it until next week, so it may be awhile. Thanks for your information on Randy Farley's work.

[afriend]

funny thing reading this, my uncle is about your age an electrical engineer and worked on the ground tracking electronics for one of the first Apollo's. he lived in nj and worked in manhattan

Jim,

At one time there was over 150,000 engineers working on the Apollo Project. I worked for Douglas Aircraft Company in Huntington Beach, CA. This was a very exciting time in my engineering career.

[lipadj46]

I scanned over the thread not sure if this has mentioned but what most of us called TDS meters are conductivity testers that measure the conductivity of water. The only things that contribute to conductivity are mobile charged particles like ions. So conductivity testers don't see any dissolved neutral covalent compounds. Also I am a chem engineer and chemistry teacher.

[afriend]

I'm glad to know that I'm talking to a technical person who knows about water chemistry. Welcome to our discussion. Hopefully I can learn from your experience. Let me explain that chemistry was not my favorate subject in engineering school, so please try to keep it simple for my sake.

What I am attempting to accomplish with a TDS meter (one based on conductivity) is to measure the amount of disolved organic compounds in fresh water. The DOCs are from fish poop and rotting fish food (especially mosquito lavare and black worms). Do you think that the use of a TDS meter will assist me in this endevor, or am I trying to "use a telescope to see a molecule" as Eric has said?

In your response above you stated that conductivity testers don't see any dissolved neutral covalent compounds. Do the DOCs of the type above have mobile charged particles like ions.

Please feel free to educate me, I need it. Also, please address your estimate of the chances of my achieving any success in using the TDS meter.

Paul

[lipadj46]

The meter will only see organic ions. So for instance you can dissolve as much sugar (neutral organic compound) in deionized water as you can and it won't conduct but if you dissolve say acetic acid (vinegar), the organic acetate ion will contribute to conductivity. I'm not sure if any of the DOCs that we would be interested in have charges, if they are dissolving in water they would have to be either polar compounds or organic ions so there is a good probability that some contribute to conductivity. You can start by buying some distilled water, measuring the conductivity and then add some fish food or some discus crap and see what it does to the conductivity.

[judy]

this is fascinating-- keep talking, guys!! I'm learning a bunch!

[afriend]

The meter will only see organic ions. So for instance you can dissolve as much sugar (neutral organic compound) in deionized water as you can and it won't conduct but if you dissolve say acetic acid (vinegar), the organic acetate ion will contribute to conductivity. I'm not sure if any of the DOCs that we would be interested in have charges, if they are dissolving in water they would have to be either polar compounds or organic ions so there is a good probability that some contribute to conductivity. You can start by buying some distilled water, measuring the conductivity and then add some fish food or some discus crap and see what it does to the conductivity.

Good point, I'll try doing exactly that. Thanks for your input, I appreciate it.

[afriend]

this is fascinating-- keep talking, guys!! I'm learning a bunch!

Judy,

Thanks for your encouragement. As you probably know from following this thread, I suspect that the amount of disolved organic compounds play an important role in the health of our fish. I also suspect that these DOCs contribute a greater amount of concentration than nitrates, thus accounting for the reason for water changes in excess of that necessary to reduce nitrates to acceptable levels.

I'm also aware that this is not cutting edge science, but is probably known by experts in the field of acquatics. I also suspect that it is not as well known or perhaps appreciated as much in our little world of Simply Discus (judging from the response from this discussion). Certainly, I was not as aware of this as I should have been. Since I really enjoy the process of discovery (even if I'm the only one in the dark), perhaps I can learn something about the use of TDS meters, or perhaps some other method of determining how to measure of DOCs in aquarium water. After I find the way to measure it, perhaps I can get a handle on the amount of water changes are necessary.

[ericatdallas]

I found the article... here's their analysis on near zero exchange RAS systems...Unfortunately, I'm not able to share this article with anyone. I'll try to read this more thoroughly when I get the time. For those with access, I would like your input as well. You can read the abstract online as well.



"Similar to the temperature and DO, the suspended solids, dissolved organic matter and nutrient loadings are also important ecological factors in aquaculture. Organic particulates may include gill function and nourish facultative fish pathogens, in addition to contributing to the biological oxygen demand and providing a substrate for growth of heterotrophic microorganisms that may displace the nitrifying bacteria (Nitrosomonas and Nitrobacter) that are essential for the conversion of ammonia to nitrate (Summerfelt and Penne, 2005). The suspended solids and dissolved organic matter in the rearing water will also cloud the water and increase the oxygen consumption as the solids undergo bacterial decomposition. Nitrogen compounds, such unionised ammonia and nitrite, are extremely harmful in aquaculture, and their detrimental effects on rearing species have been well documented in the literature ( [Jensen, 2003] , [Meinelt et al., 2010] , [Pinto et al., 2007] and [Spencer et al., 2008] ). Phosphorus is generally considered as the limiting factor for algal reproduction in eutrophic waters (Zhang et al., 2010a), and an excess of phosphorus will lead to algal blooms that are also detrimental to aquaculture. In the present study, the final weight, survival rate, SGR and/or yield of the three main culture species (i.e., I. punctatus, S. sinensis and P. fulvidraco) were negatively correlated with the suspended solids, organic matter and/or nutrients, whereas the silver carp showed the opposite trend, indicating that the main culture species were inclined to live in meso- or oligotrophic conditions that corresponded to superior water quality and the silver carp adapted to the more eutrophic conditions that matched poor water quality. In addition, through the association of the water quality with fish production, the extent of sensitivity to the water quality for the three main species can be ordered as follows: I. punctatus < S. sinensis < P. fulvidraco."

An integrated recirculating aquaculture system (RAS) for land-based fish farming: The effects on water quality and fish production
Shi-Yang Zhanga, Gu Lia, , , Hui-Bi Wua, Xing-Guo Liub, Yan-Hong Yaoa, Ling Taoa, Huang Liub

Aquacultural Engineering
Volume 45, Issue 3, November 2011, Pages 93-102

[judy]

that posting seems to be in a strange, indecipherable foreign language that mysteriously incorporates some simple English words, like 'the' and 'of' and 'water'... anyone know how to translate this peculiar language?

[afriend]

Judy,

Don't ask me, I just know English (a little). I think it's refering to aquaculture, as it relates to fish farming. Perhaps we can get Eric to translate.

[lipadj46]

it pretty much says clean water yields bigger healthier fish and some fish are more sensitive than others.

[afriend]

it pretty much says clean water yields bigger healthier fish and some fish are more sensitive than others.


Wonder why they have to use all those words to express the obvious. Sounds almost like some government agency report.

[ericatdallas]

it pretty much says clean water yields bigger healthier fish and some fish are more sensitive than others.

Yeah, that pretty much sums it up.


Wonder why they have to use all those words to express the obvious. Sounds almost like some government agency report.

It's because unless someone does formal research on it, there are skeptics that won't believe it. Even with formal research, there are skeptics that just don't want to believe it :)

I don't know what it is about big words and journal articles. It makes it really hard to do a word search because you have to learn the way people state simple things like....


aquaponics - recirculating aquaculture system
water exchange - water change
biological oxygen demand - breathing

I'm not even sure it's done on purpose most of the time. When I write these things, a switch in my brain triggers the use of obscure and awkward terminology.

[plecocicho]

ist just scientific jargon, language. every scientist in that field knows what those words mean. Articles like this ar meant for the scientist, not the general public. Basically it says, that D0 can have neagtive affect on the culturing fish by a) clogging or irratating gills b) heterotrophic bacteria prevail and hinder the growth of nitryfying bacteria via competing for the oxygen and nutrients c) oxygen consumption for biological degradition of DOc.

[ShinShin]

Why? Not just nitrates. Eric's comments and the article, IME, are right on. My experiments in raising fry from the same spawns in seperate tanks with different water change percentages showed that the larger volume w/c's produced larger discus. Experiments with adults showed that daily water changes of 40% or larger compared to 100% weekly produced superior results for having healthier and more vibrant discus.

As Eric said, there is more to it than nitrates. There is alot of other compounds that need to be elimenated. I hear people talking about their thriving discus and once a week water changes, yet in threads where a novice asks how old a discus lives to, most of these once a week w/c folks reply 3-4 years. Few believe that a discus can live to be close to 15 if properly maintained. Alot of discus disease is resulted to a compromised immune system caused by stress. Water parameters are a key to added stress. I believe that over time, this continuous stress breaks down its immune system, and the fish becomes ill. Then its a guessing game as to why. Long term effects of poor water and, while were at it, poor diet. I am willing to bet that most deaths come from this. The stress was the cause of an oppurtunistic pathogen being able to overtake the discus. Clean water of the proper parameters, and good food are essential for really healthy, thriving discus. Simply being alive and not showing disease symtems is not necessarily "thriving".

Mat

[lipadj46]

Why? Not just nitrates

I can understand why people are incredulous. Every other aquarium website you visit downplay water changes even with discus. Another very educated (is getting his doctorate in the ecology of aquatic plant enviros) planted tank enthusiast will argue that nitrates do not effect fish unless up in the 100s of ppm and that for the most part this daily water change stuff is hogwash. He has discus too. Me I stick with water changes because I've personally witnessed the negative results if I don't.

[3dees]

if it's working for you why change? most members here have forgotten more about discus than I know, but it seems that sometimes we can go a little overboard. I'm not saying it's wrong. I have eight adult wilds in a 120 gal. tank. simple setup with sand, lots of wood, and some floating plants, running two cannisters. I do a 70% wc every 5 days. tank has been running for over 18 months. I have never added anything to my tank except for prime with tap water. my fish are active and healthy. what more can I expect? I believe in keeping it simple and if your happy with your tank and fish, then just keep doing what is working for you.
Danny

[ericatdallas]

I can understand why people are incredulous. Every other aquarium website you visit downplay water changes even with discus. Another very educated (is getting his doctorate in the ecology of aquatic plant enviros) planted tank enthusiast will argue that nitrates do not effect fish unless up in the 100s of ppm and that for the most part this daily water change stuff is hogwash. He has discus too. Me I stick with water changes because I've personally witnessed the negative results if I don't.

I think the problem, especially with the scientist is the scope of the research they're involved with. Most of the research on fish is for food fish. That's where the money is and that's where the emphasis is ... solving world hunger.

So 100ppm does not effect fish that live to... what? 3 months? 4 months? A year? As Mat said, a discus can live for years if not over a decade taken care of... we see this with people. Healthy environment, medical care, and plenty of healthy food and people live well passed the average. The ever increasing lifespan of developed nations demonstrates this... of course, we can go overboard as we see with heart disease, diabetes, and obesity and so can fish.

Another problem is, people (even scientists), see research and they preach it as gospel. Yes, fish can 'thrive' in 100ppm and even up to 1000ppm of nitrates with no 'noticeable effects' as compared to control groups. What timeframes are we talking about? What are our metrics? Purely weight? What confounding factors are there? If you're comparing nitrate levels, is there something hindering all their growth that you're not measuring for---your unknown unknowns versus your known unknowns for those experimentalists out there.

Further, research consistently shows that FRESHWATER fish do require low nitrates for development. There is a high correlation between nitrates and juvenile fish in both formation AND growth.

In summary:

- What are your goals? Lifespan may not matter.
- What is the age of the fish? Nitrates may not matter (as much) for adult fish (which is what's taught in this forum - get adults for beginners and planted tanks).
- What is your metric for 'healthy' and 'thriving'? I've seen plenty of football fish that people say, "Hey, look how healthy my discus are." Plenty of people calling their 4" discus 6" (Fish hobbyist measure their fish like men measure their... ahem).
- Aquaculture is still in it's "infancy" as compared to more established fields. There's a LOT to learn. Aquaculture utilizes many advanced scientific fields and the glory and money hasn't quite reached it yet. It requires a lot of multidisciplinary knowledge. I actually have a lot of respect for aquaculture engineers. It's like biomedical engineering --- you need biology, botany, chemistry, electrical, mechanical engineers, etc. Heck, I'm probably leaving out half of the support of very smart people when it comes to building these things.... civil engineers, systems engineers, software engineers, environmental engineers, veterinarians, etc?

[ShinShin]

And because of what is driving research is solving food problems and not hobbyists concerns, if one reads more than this forum or other forums, scientists have stated in articles that much of what science has learned is due to information serious hobbyists have passed onto the scientific community.

Mat

[afriend]

I didn't mean to stirrup a bees nest with this subject of water changes, just trying to get a handle on the amount of water changes to raise sub-adults to adulthood and then keep them happy and healthy. I do not advocate that water changes be reduced to the minimum, I'm just trying to get a handle on how much is reasonable. This endeavor has got me thinking, and I have made some changes as well as thinking about what is going on in the tank that requires water changes. I was making w/cs of 75% weekly because that resulted in keeping nitrates below 5 ppm, and I know that nitrates at this level are far below the level that would harm my adult discus. I have since changed my w/c schedule to 50% daily until such time that I can determine something more reasonable.

I now suspect that nitrates are not the only water parameter that is important. I'm guessing that disolved organic compounds (DOCs) play a very important role in healthy fish and that a measure of nitrates may not give one a good handle on the level of DOCs. DOCs result from uneaten food and fish poop. The amount of DOCs will probably vary greatly depending on what is feed as well as how one feeds the fish. It could well be that keeping the nitrates below 5 ppm does not keep the DOCs below healthy levels.

So I thought I might try an experiment where I use a TDS meter to estimate the level of DOCs in my tank, as a function of w/cs. As has been mentioned here on this thread, a TDS meter may be useless in measuring DOCs. This may be the case, and my attempt fail as a result, but I'm going to try anyway.

I would be greatly appreciate if any of you could give me guidance on how to go about this process of measuring DOCs using a TDS meter. Also, please feel free to suggest any other approach that you think might work.

Paul

[Second Hand Pat]

What about using PP?

[ericatdallas]

I would be very interested in what you come up with... especially an experienced engineer. Some of the stuff you're talking about doing (if done right) take equipment. I'm not saying it's not poissible, there are people trying to build research fusion laboratories in their basement so if you have the drive, skills, and resources....

[afriend]

What about using PP?

Don't understand your question. What is PP?

[lipadj46]

Don't understand your question. What is PP?

potassium permanganate,an oxidizer that turns from purple to brown when it is "shot", the more organics in your water the faster the reaction.

[afriend]

I would be very interested in what you come up with... especially an experienced engineer. Some of the stuff you're talking about doing (if done right) take equipment. I'm not saying it's not poissible, there are people trying to build research fusion laboratories in their basement so if you have the drive, skills, and resources....

I would not put measuring DOCs in the same classification as building a fusion laboratory. Perhaps if you could be more helpful by pointing me in the right direction.

Paul

[afriend]

potassium permanganate,an oxidizer that turns from purple to brown when it is "shot", the more organics in your water the faster the reaction.

Thanks, I'll look into that. Anything else you can think of?

[ericatdallas]

I would not put measuring DOCs in the same classification as building a fusion laboratory. Perhaps if you could be more helpful by pointing me in the right direction.

Paul

That was my point. I was sayting that people are so clever they are able to accomplish a lot of things. My point was, I was interested in seeing how your project works out and to see how resourceful you are at getting this up and running. If people can get fusion in a warehouse with DIY, then I wouldn't doubt anyone in doing anything.

Sorry I wasn't being helpful. My comment was actually meant as encouragement.

[afriend]

That was my point. I was sayting that people are so clever they are able to accomplish a lot of things. My point was, I was interested in seeing how your project works out and to see how resourceful you are at getting this up and running. If people can get fusion in a warehouse with DIY, then I wouldn't doubt anyone in doing anything.

Sorry I wasn't being helpful. My comment was actually meant as encouragement.

I owe you an apology, I misread your intent in your response. Thanks for your encouragement.

Paul

[Second Hand Pat]

Paul, I was wondering if you could play with drawing a correlation between the PP burn rate (color change) and your TDS meter measurement for a particular water sample. I am truly pulling at straws here since I have messed with neither PP or a TDS meter. I was "brain storming" without a lot of info so consider it a WAG.
Pat

[ericatdallas]

I owe you an apology, I misread your intent in your response. Thanks for your encouragement.

Paul

LOL, re-reading it, I can see where it could be read and interpreted with a lot of sarcasm. That definitely wasn't my intention. No worries :)

My thought process when I wrote earlier was actually so over-the-top I didn't even think to mention it. I remember reading a while back that there was a group trying to make a Spectrophotometer and I laughed to myself about it ... then I remembered the backyard nuclear physicist that was arrrested this summer and then I remember the guy who was attempting nuclear fusion in New York. Lots of DIY science going on out there...

Anyway, I only have a basic understanding of spectroscopy, but that was the only thing I could think of which seemed kind of absurd to me so I didn't bother to mention it...

I do think Pat's idea is worthy of further exploration.

[Second Hand Pat]

Thanks Eric :)

[judy]

I think this thread is fascinating, and I hope you continue it, Ifriend. I am looking forward to learning more as you research the subject.

[afriend]

I think this thread is fascinating, and I hope you continue it, Ifriend. I am looking forward to learning more as you research the subject.

The TDS meter is scheduled to be delivered Tuesday. Don't hold your breath. I would only rate my chances of being successful in using it to accomplish my intended purpose as minimal at best. This may be another of my idiotic endevors. But then again, who knows, I may be surprised. I will get back and report one way or the other.

Paul

[afriend]

LOL, re-reading it, I can see where it could be read and interpreted with a lot of sarcasm. That definitely wasn't my intention. No worries :)

My thought process when I wrote earlier was actually so over-the-top I didn't even think to mention it. I remember reading a while back that there was a group trying to make a Spectrophotometer and I laughed to myself about it ... then I remembered the backyard nuclear physicist that was arrrested this summer and then I remember the guy who was attempting nuclear fusion in New York. Lots of DIY science going on out there...

Anyway, I only have a basic understanding of spectroscopy, but that was the only thing I could think of which seemed kind of absurd to me so I didn't bother to mention it...

I do think Pat's idea is worthy of further exploration.

I agree that Pat's idea is worth investigating.

Paul

[Second Hand Pat]

Paul, please post the results/observations whichever approach you take :)
Pat

[ShinShin]

Does a TDS meter register this sort accumulation. I thought it registered total charged anions and cations? And, why subject your fish to constant PP treatments instead of changing water?

Or, am I reading this all wrong?

Mat

[Second Hand Pat]

Mat, this would not be done on water containing fish.

[Rummy]

Fascinating thread. Keep it coming!

Anik

[afriend]

Does a TDS meter register this sort accumulation. I thought it registered total charged anions and cations? And, why subject your fish to constant PP treatments instead of changing water?

Or, am I reading this all wrong?

Mat

Mat,

I'm attempting to use a TDS meter to measure disolved organic compounds (DOCs) in aquarium water. The manufacturer (Hanna) claims that it will measure some types of organic material disolved in water. I'm not at all convinced that I will be successful at doing this, but I consider that its worth a try.

The use of PP is another way of measuring DOCs. The measuring process involves taking a sample from the aquarium and testing it by placing an amount of PP in the sample. I'll consider this method if the TDS meter method doesn't work. As Pat said, I don't intend to put PP in the tank. (Some types of sickness are treated using PP in the tank.)

If you have any suggestions on how to accomplish this using a TDS meter, please feel free to offer them.

Paul

[Skip]

i hope you have done at least ONE water change since the start of this thread!! lol

[Rummy]

This could be a fun little experiment for those that are interested. It is always good to have repeatable results on any study.

Anik

[afriend]

[I]
i hope you have done at least ONE water change since the start of this thread!! lol

Warlock,

Yea, for sure. I've been making 50% daily changes for several days now. Will continue this w/c rate for awhile.

[Stag]

I just got done reading all 5 pages. It's been a while since I learned to much from a thread. I think it is good to know why we follow the rules we do.