Overfiltering? In some cases, yes

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

fish_4_all

Aquarium Advice Addict
Joined
Mar 13, 2005
Messages
1,864
Location
Aberdeen, WA
I think there has been a really important point that has been overlooked in the discussion about overfiltering. That is the fact that only a certain number of denytrifying bacteria will grow depending on your bioload.

Example: I have an aquaview running in my 10 gallon tank and I have the smallest sponge filter I could find. The aquaview has no discoloring in the filter floss and therefore I would assume no beneficial bacteria. The sponge filter is almost nasty looking after 2 weeks and definately has a massive amount of beneficial bacteria.

If I was to take out the sponge filter, could it not cause an ammonia spike because the aquaview doesn't have the bacteria? When I set up my Aquaclear, will it get the needed bactrerial growth for me to remove the sponge filter? I have my doubts about that.

I guess the real point is that if you do not plan to keep all the filers running in a tank that is overfiltered you can most definately overfilter and run the risk of a disaster if they want to reduce the amount of filtration.
 
reducing bio-media slowly to allow the surfaces that were not being used to catch up is important. it is a good observation and is likely not discussed enough with the overfitation argument. (y)
 
The aquaview has no discoloring in the filter floss and therefore I would assume no beneficial bacteria. The sponge filter is almost nasty looking after 2 weeks and definately has a massive amount of beneficial bacteria.

i'd like to contradict the statement.
discoloration of a filter media is caused by clogging of finer pores by debris like solid fish waste, dead plant matter and other DOC's. this causes an rapid growth of heterotrophic bacteria (that use organic carbon as their food source and break down the DOC's). these grow much faster than beneficial or nitrifying bacteria (nitrosomonas and nitrobacter) and can dislodge them.

so, effectively, your relatively clean aquaview might have a larger colony of nitrifying bacteria than your dirty sponge filter.
 
Hmmm, sounds interesting. I don't use carbon in my aquaview but I don't think that is the carbon you are refering to. As for the filter floss in front of the filter cartridge, I thought it was supposed to get some color to it after a few weeks of use? Might be wrong but isn't that where the nitrifying bacteria grow in an HOB? I use the cartridges but I remove the carbon before using them, replacing or washing them every other water change.

I just want to make sure that when I get my aquaclear set up and running that I can remove my sponge filter until I am ready to breed my corydoras.
 
you are right. it's dissolved organic carbon and not the activated carbon that i'm talking about.
i've never used anything other than an aquaclear 9with a sponge and a bag of biomedia), so i'm not very sure about other filter media. but from common sense, your filter media should have collected some debris, unless you do almost daily pwc's and maintain a non-planted and low-bioload tank (which i think you don't).

the science of biological filtration has still not advanced very far. so, all i can offer are conjectures. i'm sorry, but i can find no logical explanation as to why your filter floss is not dirty. all i can safely say is that at moderate temperatures (around 78C), your new filter should be completely colonized in a month.
 
Well that sounds good to me. I agree that there should be a good maount of bacteria in the filter, at least enough to multiply enough to eventually handle the tanks needs. I guess I am also missing the fact that bio-filtration needs oxygen and the HOB is going to have a lot more oxygen than is going to reach the surface of the sponge filter. The only oxygen it gets is the dissolved oxygen.

I do water changes every week, on Tuesday. 2/5 to 1/2. The tanks are not planted but has a lot of java moss in my moss keepers and anacharis floating around. I wish I could find a plant that would take root once it is planted but I have yet to manage that one.

I like conjecture. It gives a place to start. I know that a person can tell how well an established tank is working by taking readings. Monitoring the tank after a major change will tell you what is happenning. Why it happens and what causes it is conjecture. If I knew how to test it and monitor the possible causes, I would have something I could write a book about.
 
Here is the big question. Should my aquaclear be able to maintain the bioload once I remove the sponge filter in about 3-4 weeks even if it doesn't get the discoloration like the aquaview hasn't?
 
you are absolutely right - the hob's are designed to have higher flow rates than the largest sponge filter operated by an air pump (well a bit exaggerated). so naturally there's a higher rate of flow of oxygenated water through the hob, resulting is a more efficient filtration. so, even if you have a smaller number of bacteria there, they should be working with a higher degree of efficiency (think of it as you working in a well-ventilated room compared to a stuffy room).

anyway, enough with conjectures :wink: . i'm pretty sure the AC will be suitably seeded in a month and you can remove the sponge filter.
as a sidenote, once i kept the sponge of a used sponge filter on top of the filtering media in the AC to seed it. i was using a AC300 with a sponge and biomedia (no activated carbon). so i had plenty of space left on the top of the AC.
 
I agree, the HOB filter media should be thoroughly seeded after 3-4 weeks. You shouldn't see any kind of mini-cycle when you remove the sponge filter, but don't add any fish (if you were planning to) for a couple weeks just to play things safe.
 
Back
Top Bottom