Biofilter and water changes

[Albanets]

Stupid question, but...
I was always wondering: a biofilter consists of 2 types of bacteria - one converts ammonia to nitrites, and another nitrites to nitrates. Nitrates can be removed by water changes only.
As I understand, the more water changes you perform, the better. Ideally, you should do 100% twice a day.

But if you constantly remove all ammonia from the water, most of bacteria should die due to the lack of "food"??

[Timbo]

yup, the filter will only support as many bacteria as there is food to feed them. if you lower the ammonia, you lower the bacter count...but you wont be able to remove all of the ammonia (its being produced constantly by the fish) unless you have a river of new clean water running thru your tank constantly (in which case you would not need a filter at all). even twice a day, 100% water changes will still produce some ammonia that will be available to the aerobic bacteria in the filter...hope that helps :)

[Elcid]

"The bugs" that convert ammonia to nitrite and nitrIte to nitrAte are living organisms and as such are born and die continuously. When they die they sluff off the biomedia as solids and are removed by your water change and when you squeeze out ur sponge daily.

The amount of active biopopulation depends on the bioload. If the bioload is continuously zero there will be none. If the bioload fluctuates, more "bugs" will be born when it's high and less "bugs" will be born when it's low.

Death occurs both naturally and by starvation. In chemical plants that have wastewater treatment systems to treat their effluent they sometimes feed a continuous supply of food to their biosystems because their normal bioload is very low so that if they get a peak there will be a sufficient biopopulation to react quickly and handle the load.

It's always best to have a continuous an constant bioload in any wastewater treatment system.
HTH,
Sandeep

[Albanets]

Thats what I thought.
It comes down to that "optimum" amount of bioload must be present to sufficiently maintain a biofilter. Of course, it must be as low as fish can handle without stress, but it must be in the system.
I read sometimes about guys who make massive water changes and suddenly fish are stressed at some point. Of course, it could be anything, but I wonder if they overfed fish a day before and "weak" biofilter just could not handle ammonia swings.
Experinced guys know this intuitively, do they? ;)

[Elcid]

It's not like that. All organisms are creatures of habit; given constant routine/conditions they will adjust and thrive. But, when conditions are constantly changing they are unhappy and even die!

[White Worm]

Hey Albanets... I have had that experience with the large water change and then problems. I think though that it stems from not being able to store, age, aerate and treat the water prior to wc. I believe it has alot to do with lack of oxygen in my case. Everyone that I have heard of that has had this problem, has been doing changes straight from tap. It may be chlorine, chloramines, co2 or lack of oxygen. There was no gas-off period and I think they were poisoned or suffocated. Thats just my logical conclusion about what happened to me. It was a 90% wc and then disaster. I had no problems before that and I regularly did 30% every day. No more wc's more than 50% for me until I set up water storage. Mike

[cobaltblue]

Hey MIke, yeah, its was your story a while back that made me make sure i didnt do water changes of more than 50% , as i dont have room for a water storage unit, and my wife especially does not want it...eyesore. There is nowhere for me to hide it away out of site. So i do tap changes, but never more than 50%, and so far its been awesome. i have spawns all the time, but no babies yet. None of my fish are over a year old, so it will come in time.;)

[Alight]

OK, think about it this way. If you have an adequate biofilter, you will NEVER have measurable amounts of ammonia or nitrites in your water. It doesn't matter if you did no water changes or water changes every 5 minutes. You need a good flow of water through your biofilter to accomplish this, but nothing else. (the ultimate result would be very high nitrates with few or no water changes, though, so don't try this).


The reason is that with an adequate biofilter, the bacteria are present and active enough to convert any ammonia produced by your fish (or breakdown of their food or feces) to nitrites and then to nitrates virtually instantaneously. Think about it in terms of calculus, not linear equations. It is the rate of production of ammonia that is important, not the actual amount of ammonia. This rate of production is independent of water changes (unless you are sloppy and allow a bunch of food and feces to build up in your tank between changes). Therefore, water changes will make no difference in the adequacy of your biofilter and your biofilter will be well fed (unless, of course, as someone already said--the water is changing over constantly in large quantities, in which case the effective amount of ammonia production that is getting to the biofilter could end up being zero).

The only time that ammonia levels help build the biofilter is during initial cycling, or when adding more bioload. At this time, higher levels of ammonia will speed up the build up of an adequate biofilter. However, note the words "speed up". An adequate biofilter can be built up even with daily water changes, and very little, if any measurable ammonia build up --it will just take longer.

I agree with the others above who indicate that water change effects on the biofilter weren't due to dilution of the ammonia and nitrites, but due to other factors in the changed water that were detrimental to the nitrifying bacteria.

[Albanets]

lol, the other way around: guys who can store, preheat and aerate water to do 90% WCs a day NEVER overfeed... :D

I totally agree that one should not do more than 50% WCs.

[White Worm]

Chris....Yeah, same for me. The wife definately doesn want anything else in the house that even resembles fish equipment. 85g, 75g and 35g in the house now and the wife said thats enough. Since that problem, I have been sticking with 30-50% and they are all doing fantastic. I am planning my fish room now in the garage and I will then have stored water and not have to worry so much. I always 2x dose prime just to make sure and I have plenty of current, air and surface agitation in all my tanks. I think it is more important for the little guys though. Adults seem to do fine with just a sponge filter with a nice flow of air. I only do 20-30% changes with them. Live and learn right?

[Albanets]

OK, think about it this way. If you have an adequate biofilter, you will NEVER have measurable amounts of ammonia or nitrites in your water. It doesn't matter if you did no water changes or water changes every 5 minutes. You need a good flow of water through your biofilter to accomplish this, but nothing else. (the ultimate result would be very high nitrates with few or no water changes, though, so don't try this).


The reason is that with an adequate biofilter, the bacteria are present and active enough to convert any ammonia produced by your fish (or breakdown of their food or feces) to nitrites and then to nitrates virtually instantaneously. Think about it in terms of calculus, not linear equations. It is the rate of production of ammonia that is important, not the actual amount of ammonia. This rate of production is independent of water changes (unless you are sloppy and allow a bunch of food and feces to build up in your tank between changes). Therefore, water changes will make no difference in the adequacy of your biofilter and your biofilter will be well fed (unless, of course, as someone already said--the water is changing over constantly in large quantities, in which case the effective amount of ammonia production that is getting to the biofilter could end up being zero).

The only time that ammonia levels help build the biofilter is during initial cycling, or when adding more bioload. At this time, higher levels of ammonia will speed up the build up of an adequate biofilter. However, note the words "speed up". An adequate biofilter can be built up even with daily water changes, and very little, if any measurable ammonia build up --it will just take longer.

I agree with the others above who indicate that water change effects on the biofilter weren't due to dilution of the ammonia and nitrites, but due to other factors in the changed water that were detrimental to the nitrifying bacteria.


Your point is that once biofilter is established, it will take care of any ammonia spike no matter how big it is?

I guess, nobody did precise experiments?
The system must be in equilibrium, and when you cycle, initial amount of ammonia is high and number of bacteria is low. Hence, bacteria start multiplying and reduces ammonia. When ammonia amount is reduced, bacteria population adjusts - it partially dies off. The system reaches equilibrium. We say that a tank is 'cycled'. All produced ammonia is immediately 'eaten'.

Now, if you rapidly increase bioload at this time point (by introducing new fish, overfeeding) bacteria colony will be able to consume it, but whithin its 'capacity' to do so. If the colony is not big enough, it will multiply to reach new equilibrium and eventually consume excessive ammonia. However, negative effect on fish is immediate.


IMHO :))

[Alight]

"Your point is that once biofilter is established, it will take care of any ammonia spike no matter how big it is?"

No and yes. In practice, no, because you can add enough ammonia through increases in bioload to cause a toxic amount of ammonia to accumulate, no matter how much you change the water.

Theoretically, yes, because as long as you have a well established biofilter, and you have excess surface area for the bacteria to grow on, if you increase your water changes enough, you will keep your ammonia levels well below toxic levels, and often, below detectable levels, and yet your biofilter will still expand so that you can gradually decrease your water change levels to whatever is necessary to keep your nitrates low enough.

The point is that the ammonia in a tank with an established biofilter should never be detectable, and can be kept at that level with proper care and reasonable additions to the bioload.

The other point is that a well established biofilter is "dispersed" and has additional capacity for ammonia beyond the amount it normally consumes. It also can rapidy increase when the rate of ammonia production is increased. These bacteria can actually double their number in 24 hours. Now this is slow by bacteria standards, but this would mean that you could double your bioload and they would catch up in 24 hours.

Do they die if ammonia is cut off? Yes, but this takes some time--several days--they inactivate before they die and can recover from this state very quickly. If kept cold, they can survive much longer. Marineland has figured out how to store them in a chilled environment for several months.

It would be nice to know how many days they can actually survive in a heated tank with no ammonia source.

[Albanets]

Very clear answers, thank you! Now I see what is going on. :)

[Ichthyology]

Rememebr, ammonia becomes NON toxic in pH's below 7. So if you keep your tanks at 6.0-6.5 you will not have to worry about ammonia toxicity, per se (the amount of the toxic form is very low). With regular water changes, the amount is so low.................

[Resinman]

[QUOTE=Resinman]Just to add my 2 cents. Actually you can remove Nitrate and Nitrite with exchange resins.

[Alight]

Yes, you can remove ammonia and nitrate and prevent nitrites with ion exchange resins. You can also remove nitrates with anerobic denitrators.

However, you won't remove many non-polar dissolved organic compounds that are also produced in the breakdown of food and feces. Bacteria feed on these as well, and some of them are toxic. What this means is that you will get nice low readings of nitrates, ammonia and nitrites and will have a false sense of security about how pure your water is.

Water changes are the only answer.

Been there, done that.

[pcsb23]

Yes, you can remove ammonia and nitrate and prevent nitrites with ion exchange resins. You can also remove nitrates with anerobic denitrators.

However, you won't remove many non-polar dissolved organic compounds that are also produced in the breakdown of food and feces. Bacteria feed on these as well, and some of them are toxic. What this means is that you will get nice low readings of nitrates, ammonia and nitrites and will have a false sense of security about how pure your water is.

Water changes are the only answer.

Been there, done that.

I believe this used to be called old tank syndrome, when a previously well established and functioning tank suddenly loses all its inhabitants!

There are many ways we can minimise the effort involved in looking after our fish, and many of these newer devices help us achieve our goals. Appropriate and regular water changes correctly carried out is still imo the best guarantee of success.

Paul.

[Resinman]

Yes, you can remove ammonia and nitrate and prevent nitrites with ion exchange resins. You can also remove nitrates with anerobic denitrators.

However, you won't remove many non-polar dissolved organic compounds that are also produced in the breakdown of food and feces. Bacteria feed on these as well, and some of them are toxic. What this means is that you will get nice low readings of nitrates, ammonia and nitrites and will have a false sense of security about how pure your water is.

Water changes are the only answer.

Been there, done that.

Totally agree but we also have to admit we are talking only about one aspect of filtration. Water changes are great and can be automated to make them even easier but paying attention to cleanliness and the mechanical filtration end of your filter system controls the organics. There is something to be said for the "X" factor in an established central system. The older the water gets the better it is. To each there own. The advantages to a central system and controlling the water with exchange resins in my case out way the negatives. Besides the chemistry end of it has always intrigued me.

Anyways as spiderman once said "nough said"

[raglanroad]

Taking into account the various viewpoints with good reasons included, the thing that it seems to point to is that this condition is not one of "new tank syndrome". The high nitrates would not be that high from the tap most likely.

So if it was from too high bioload, with just the 2 fish, the filter should have caught up already.

The points about clogged filter and the need to free the pores up from food ; as was mentioned, the filter will eat ammonia , but food gets eaten first by some types of bacteria of a group called heterotrophs (amongst which are some nasty ones) . So the water could be in poor state, and you should squeeze out the filter more often- especially if doing this changes the ammonia problem.

If the pH is low, you won't have too much problem from the ammonia. Just maybe a bit of caution if water changes bring the pH up but you still have ammonia. So it seems either keep the pH low while you change out the water a few times over , or use an ammonia killing product and change out the water anyway.

[Willie]

... There is something to be said for the "X" factor in an established central system. The older the water gets the better it is. ...

This is, of course, nonsense. There is no "X" factor. Older water is not better water.

Problems with biofiltration instability usually stem from insufficient colonization of the sponges. I make 100% water changes weekly. Every surface, including the heater and the filter tubes, is scrubbed. The sponges are squeezed until the water is clear. Add tap water back in with AmQuel. Zero cloudiness. Well cycled sponges have more than sufficient bacterial population to react to ammonia production.

I have multiple breeding pairs in 40-gal breeders that get this treatment. Half the time they will spawn within 2 hours of a water change. If you are not making major water changes, the water is simply not clean. Those of you who belong to the North American Discus Association are welcome to read about the chemistry of water changes on their website.

Willie