Nitrifrying Bacteria

C

crash

AC Members
Feb 26, 2003
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Clintonville, WI
www.rejected.ws
Not sure if I spelled that write in the subject, anyways I want to get some more information clarified about the 'good bacteria' that is fully established after a tank cycles, whether it's fish-less or with fish.

I do a water change with both my 10 gallon tanks, once a week (5-7 days usually), however with a water change I always vacuum the substrate, I usually vacumm as much as I can getting out left-over food and such. I don't vacumm portions, I pretty much vaccoom all I can accept under my decors.

Now I've heard a lot of things whether they be the truth or myth, but can you vacuum your tank to much? I've heard a lot of people say, right on these forums, that you should do vacuum in portions so you don't take out most of your nitrifing bacteria, or do one side of the tank etc...

Replies and thoughts would be appreciated. Thanks.
 
No you cannot vacuum the substrate too much, that is mythology. It was wise of you to recognize something mot quite straight in that advice and to ask for clarification.

1. Nitrification or nitrifying bacteria (aka lithotropic bacteria) are very firmly attached. In fact they are unable to metabolize and grow if they are not attached. If vacuuming the substrate could remove the bacteria, then fluidized bed filters - which are in effect vacuumed 24/7/365 - could never establish or function. And they do function.

2. The nitrification bacteria have a high and absolute requirement for oxygen, along with their 'food' of ammonia or nitrite. therefore they will establish wherever there is the best O2 and 'food' supply (i.e., constant current) and those conditions should be in the filters. If you prevent them living in the filters by throwing away the media and replacing with new routinely, then they will go to the next best places, which may or may not be in the gravel. So for most folks who maintain their filters wisely, what they do to the gravel has little effect on nitrification in any case.

3. If you filter is UG, then you need to be particularly conscientious about vacuuming, to prevent debris from burying and suffocating your nitrification bacteria - which will be on the gravel in this case as it offer the best flow and therefore food and oxygen.

HTH
 
I have been guilty of spreading my own misconception that bacteria can be "dislodged" from their site. RTR rightly corrected me. They're on as tight as the plaque on your teeth!

The compost, or humusy floc that develops among the hard grains in the substrate is also a solid site for bacterial colonies. For colonizable surface, compare a baseball and a bath sponge of the same dimensions. This is the stuff that binds iron and other positively-charged nutrients in the substrate. Then phosphate adsorbs to the cations. In a planted tank, this is good.

Some planted tanks are so well covered by low-growing ground cover, you can't vacuum the gravel at all. No one comes to grief, however...

Remember, you can also flush debris off the surface at water changes. It gets quickly caught up in the filtration, and eliminated with a filter-rinsing...
 
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