Bio-filter weak?

[Scales]

By doing daily water changes, does the biological filtration become weak due to the lack of "food"? Or is the waste created throughout the day enough to keep filtration healthy and basically the nitrates are just being removed during the w.c? Just wondering. Any thoughts?

[MSD]

You have to establish the bacteria for your filter first and then you can add fish and do water changes to maintain the tank and Bio bed. Read the stickies of setting up your tank and the nitogen cycle, its critical.

[Scales]

I understand the nitrogen cycle, I was just wondering if you could weaken the bio filter by keeping toxins low. Forcing a dependency on water changes to prevent ammonia and nitrite spikes.

[Elliots]

That is a good question. I do not know the answer. Does the biofilter eliminate most ammonia and nitrites or does the constant large water changes eliminate them? Or both? Many people on SD do large water changes and it works. I never thought about which, biofilter or waterchanges, does more. Which ever it is, it works.

[MSD]

My point was if the bio is already established then the water changes are fine. If you have not cycled the tank yet the water changes can impact the beneficial bacteria taking hold and prevent the cycle from finishing. So the answer is a qualified YES.

[cjr8420]

I understand the nitrogen cycle, I was just wondering if you could weaken the bio filter by keeping toxins low. Forcing a dependency on water changes to prevent ammonia and nitrite spikes.yes and no it depends on BB or substrate.BB tanks come clean no where for bio except where u have planned for it filters sponges ect.a dirty established gravel substrate will have its own bio thats stronger than any barebottom because of the amont of waste that stays trapped feeding the bio regardless of WCs compared to a BB.less waste =less bio, more waste =more bio.i believe u will have a better chance of a mini cycle in a BB tank compared to a tank with gravel.but a gravel substrate will never officially be clean imo

[SMB2]

An interesting question. If you have an established cycled tank with a bio filter, what would be the nutritional source to the "cycling" bacteria if you are doing large daily water changes?
I suspect that if you stopped the water changes you would get an ammonia spike if the bioload was constant. Perhaps not a large or long one but the bacteria I bet would have to catch up.

[Elliots]

SMB2, you could be correct. I do not know. Maybe someone on SD stopped large water changes, did they get an ammonia spike?

[SMB2]

It would just seem practical that the biomass of BB would be proportional to the overall nitrogen load. If you are doing large daily water changes and have a bare bottom tank
the N sources are the fish (ammonia and poop) and uneaten food. All are being minimized
by the water changes. Makes you wonder what the sponger filters are really accomplishing.

[Elliots]

I have a planted tank with a large bioload. My sponges take a lot of poop, food and decaying vegitation out of the water that I can see. I now rinse them 1-2 times daily in tank water. By the way I do not have sponge filters but HOB filters with sponges over the intakes. I assume that BB live in the sponges and do some biofiltration

[SMB2]

Well, they get particulate matter out for sure. But if 75% + water changes are done every day, are there enough nitrites and ammonia to drive a large BB population that would correspond to the mass of animals in the system?

[MSD]

They breathe, they eat, more ammonia from food and fish waste, depending on how many fish you keep, that supplies the food for the bacteria. Just because you do large changes, provided no bad things are in the water to kill bacteria, the tank will stay in bacterial balance provided no huge additons of fish or food impact it. An established BB will keep up with moderate increases of waste load. ALL provided your BB has completed its cycle.