Derr on me.. forgot the basic chemistry of the tank (plus misread that he only tested for nitrate):
First, the waste from fish, plants, and food breaks down and releases ammonia.
This ammonia is very toxic to fish and must be converted to nitrite by bacteria.
Nitrite is also toxic to fish, and must be converted to nitrate by bacteria.
Nitrate is not nearly as toxic, and is used by plants or algae to help them grow.
For some reason was thinking back to when another member mentioned the filter won't filter out ammonia, etc etc and didn't finish out my thought process. Also, none of my tanks are cycled/filtered.. so didn't pop up in my mind immediately, my bad!
Last edited by Myates; 10-09-2011 at 06:41 PM.