Water parameter perfectly fine even after not doing wc for three weeks

[Saif]

My water parameters are very good even after not doing wc for three weeks.
Ammonia - almost zero (or better completely zero)
Nitrite - almost zero (or better completely zero)
Nitrate - 10 mg/ml (falls within the safety level of my test kit).
All my fishes are happy and doing fine. What is the longest interval for wc that you guys have been doing. Earlier i used to do 20% wc weekly. but after the buying the test kit. I realized that I could have saved soo much water. Is it correct what I am doing or shall I switch back to 20%/weekly wc?
I have a 350 ltrs tank with 11 discus (approxx 8 months old). Eheim4+ 600 and two DIY overhead sumps with pothos at 600 ltrs/hr each. Feed them once in the morning.

[Mando]

The "Almost Zero" answer does not sit well with me. There are other benefits to water changes that are not easy to test or un-testable. I would definitely do one weekly WC as a minimum just to replenish minerals and trace elements. What is working for you now might not work for you in the long run. There are other in depth reasons to do water changes to help assist filtration and bacteria build up (good/bad) in which I never do a good job at explaining so I will just wait for someone with more knowledge to chime in.

[bluelagoon]

Do pothos remove that much nitrate? I've never used them but heard they were great for that. You'll also see lower nitrates in some planted tanks due to plants using it. But that is no reason to skimp on WC's. Like mentioned there are lots of other things in the water that need removing and replacing. End product of fish waste is nitrates. Which is only an indicator for a WC. You have plants, the indicator is no longer working because of the plants. You have alot of stuff in your water besides those indicators. DOC,TDS that build up and along comes more bad bacteria. All may seem well for months and all a sudden things go down hill. I've seen that happen so many times without regular WC's. To me 20% a week is like changing no water at all in a 90 gal. tank like yours.

[jeep]

The "Almost Zero" answer does not sit well with me. There are other benefits to water changes that are not easy to test or un-testable. I would definitely do one weekly WC as a minimum just to replenish minerals and trace elements. What is working for you now might not work for you in the long run. There are other in depth reasons to do water changes to help assist filtration and bacteria build up (good/bad) in which I never do a good job at explaining so I will just wait for someone with more knowledge to chime in.

Do pothos remove that much nitrate? I've never used them but heard they were great for that. You'll also see lower nitrates in some planted tanks due to plants using it. But that is no reason to skimp on WC's. Like mentioned there are lots of other things in the water that need removing and replacing. End product of fish waste is nitrates. Which is only an indicator for a WC. You have plants, the indicator is no longer working because of the plants. You have alot of stuff in your water besides those indicators. DOC,TDS that build up and along comes more bad bacteria. All may seem well for months and all a sudden things go down hill. I've seen that happen so many times without regular WC's. To me 20% a week is like changing no water at all in a 90 gal. tank like yours.

I think your answers are pretty good. There is more to water quality/bio load than nitrates alone.

[bluelagoon]

I find it dificult to keep things stable without decent water changes. I'm thinking about PH and ion exchange due to the metablized wastes over a period of time. Your water is different than mine, I would think. Mine has very little KH and hardly any GH. The post says nothing about the ph of the tank and what ph is going in the tank.

[dspeers]

Having been out of this for over 35 years and now reading furiously to try and catch up prior to launching a 150 tank sometime over the winter, I am fascinated by the changes. When I was in college prior to retiring my tanks (to the best of my suspect recollection) marines were much much more labor intensive and required much higher volumes of water changes. Now they are so automated that they can often go months without.

I am not objecting to the more frequent changes almost everyone does for discus tanks. There seem to be only a very few folks out there trying more prolonged intervals with variable success. Currently I plan to go with 25-30 % weekly and follow Nitrates, Ph, TDS, and ORP as indicators to increase frequency/volume of changes. Would be nice of there was a reliable quantitative indicator for both timing and volume of water to change, but so far as I can tell such a "magic bullet" test does not exist. PLEASE correct me if I am wrong and that perfect indicator is out there.

[jeep]

The best indicator I know of is in the photo's. While I don't really do 50% daily on adults, I firmly believe it's crucial in the development of juvies and even sub-adults.

These Passions were raised with 50%+ WC at an irregular 4 or so day schedule due to my traveling job. Nitrates were always around 5-10 while I was away. While they did grow out quite nice, many of them developed irregular finnage. The Curipera's in the 2nd photo received regular water changes and developed more correct finnage.
golds 08-28-18.jpg
curipera 4.jpg

[dspeers]

Thanks much for the info. I am just a little amazed/disappointed that there was a noticeable difference between a 1 vs 4 day interval given the measured nitrate level and no intrinsic filtration that would selectively reduce nitrates. On the basis of what I have read, I had it seems erroneously concluded that Nitrates would probably be a good test absent any chemical or biological filter impacting the level and that < 15 was safe for even juvenile discus. For my grow out 45 gallon (bare bottom, foam filters), my tentative plan was to check nitrates daily and change 50% whenever the level went above 10, unless Ph and/or ORP was changing more rapidly. I found that approach intuitively appealing as it would take into the account the variable waste production due both age and number of fish. Did you happen to check Ph as well? Your info certainly does validate the approach that indicators should increase water changes but not decrease.

The plan I noted prior is for my display tank, which will have adult discus and plants. How often do you do water changes in your adult discus tank?

[jeep]

I guess what I was trying to emphasize is that nitrates are not the only factor, although they are a good indicator. I got these after a long time away from the hobby. They were fairly inexpensive and they were a test for me to see if I could even keep discus again with my hectic work and travel schedule. They turned out much nicer than I had expected, but they were very healthy, quality discus to begin with. I lightly fed them Tetra Colorbits 4 times daily with an auto feeder and then pounded them with WC and homemade BH on the weekends, and as far as I remember, this fin issue became apparent at around 8 months, although I may not have noticed it developing earlier. I didn't pay much attention to ph because my water is pretty hard and maintains a very consistent 7.8, but it certainly could have fluctuated. I try to keep nitrates at <5.

On adults, I change 50% every other to every 3rd day, mainly because I feed them pretty heavily and I don't use mechanical filtration. Even though I like the growth and health feeding BH, it can also pollute the water more quickly.

[Filip]

Thanks much for the info. I am just a little amazed/disappointed that there was a noticeable difference between a 1 vs 4 day interval given the measured nitrate level and no intrinsic filtration that would selectively reduce nitrates. On the basis of what I have read, I had it seems erroneously concluded that Nitrates would probably be a good test absent any chemical or biological filter impacting the level and that < 15 was safe for even juvenile discus. For my grow out 45 gallon (bare bottom, foam filters), my tentative plan was to check nitrates daily and change 50% whenever the level went above 10, unless Ph and/or ORP was changing more rapidly. I found that approach intuitively appealing as it would take into the account the variable waste production due both age and number of fish. Did you happen to check Ph as well? Your info certainly does validate the approach that indicators should increase water changes but not decrease.

The plan I noted prior is for my display tank, which will have adult discus and plants. How often do you do water changes in your adult discus tank?

My modest math logic and opinion is that if we do WC s lower than 50% Nitrates should slowly but constantly accumulate .
Nitrates can be easily controlled with plant mass or De-nitrate resins but common experience shows that that alone won't lead to you to optimal growth results with discus . It appears that so far there isn't any " magic test" available that will monitor the need for WCs for optimal discus growth . In lack of such test my opinion is that the Golden rule of "the more WC the better " still applies when it comes to optimal discus growth .

[jeep]

Filip, there was a member once that laid your statement out on a graph. It was a great visual aid. I've looked for it but haven't been able to find it.

Basically, if you wait 4 days then the organics increase by 800%. If you do a 50% WC you reduce them by only 25% of your goal, etc... I tried to duplicate it but I confuse myself, lol...

Please, don't anyone test my numbers. They are from memory, lol...

[Megalodon]

My modest math logic and opinion is that if we do WC s lower than 50% Nitrates should slowly but constantly accumulate .
Nitrates can be easily controlled with plant mass or De-nitrate resins but common experience shows that that alone won't lead to you to optimal growth results with discus . It appears that so far there isn't any " magic test" available that will monitor the need for WCs for optimal discus growth . In lack of such test my opinion is that the Golden rule of "the more WC the better " still applies when it comes to optimal discus growth .

There would have to be a study that measures some water parameters and discus growth that finds some correlation.

You would need a number of genetically related fish subject to different care.

It's likely some breeders (Stendker) have already experimented with this and know.


Nitrate can never accumulate indefinitely as long as you do water changes.

Assuming a 100 L tank and 0.5 mg/L increase in nitrate per day.

50% per week

50 pct q7d.png

25% per week

25 pct q7d.png

10% per week

10 pct q7d.png

[Sturiosoma]

You can safely and should do a 30% water change a week and 30% is just that whether it's a 10 gal or 90gal, and by safety I mean you can do this with out upsetting your parameters, mainly ph I would get in the habit of checking ph in your tank before a water change and also check ph of your water change source just to be on the safe side as a ph swing is going to be the most detrimental.

Thanks Jeanne

[dspeers]

water change data.jpg

Thanks for all of the info. Had not given this enough thought and was fascinated and surprised by the final steady state value as well as by the curves and the variance in # of water changes required to reach steady state. I put it on a SS and tried to attach, will see if that works when I post, but what I am seeing is not a pic of the SS. If that is a fail I can e-mail a copy and will have to find out later how to successfully attach a gif or jpg file.

Would imagine that the commercial breeders do have this info as water would be a large sunk cost but would probably view that data as proprietary. How the reef tank folks were able to reduce water changes as much as they have is all the more impressive now that I see just how fast/high things can accumulate.

I find formulas fun and this does lead to one that might be handy as you can play with frequency and % change to see how they would affect certain levels, but not sure what beyond nitrate it would apply to, other than as a theoretical concept to estimate the concentration of a given substance based on water change effects. x=y*d*(1-w) Where x is the final concentration just prior to a water change, y the daily production of a given substance, d is # of days between water changes, and w the % change expressed in decimal form, e.g. 50% would be 0.50 for instance x=.5*7*1/.5 or 7 or another way to look at it is that 50 % changes weekly result in a 14 fold increase in whatever is added either by fish or food and not reduced by other means.

[dspeers]

Wow, the attachment did work but I missed the top row, columns 2 and 3 are 50% weekly, 5 and 6 25% changed weekly, and the last 2 columns 10% changed weekly.