<a href=showthread.php?s=&postid=9793173#post9793173 target=_blank>Originally posted</a> by papagimp
okay, I"ll explain this a little differently, it's not the ceramic rings, or anyother biomedia that is "producing" nitrates at all. It's strickly the type of beneficial bacteria on them. Light has nothing to do with it. It's all about the oxygen reaching the bacteria. In areas of high oxygen saturated water, such as what you'll get with a wet/dry filter, bioballs, biowheels, and even the canister filter with rubble rock or ceramic rings, the bacteria on them is getting loads of oxygen, this type of bacteria will convert ammonia into nitrite and on to nitrate, but will not eat up the nitrate. YOu need an anerobic zone with that type of bacteria to actually convert the nitrate to the nitrogenous gases that escape our systems thorugh surface agitation. You get this from DSB, and even in rock with bacteria colonized deep within the rock.
The reason people suggest ditching the songes is that they do not keep them clean enough and bacteria will colonize on them, same bacteria that colonizes on other forms of media, like the bioballs and whanot. Same high oxygen type of area. There fore, they won't do nothing for nitrate. Nitrae must be removed naturally, or with water changes, it's not going to go down on it's own without either of these things happening. If you removed all sponges/prefilters/and anything else that may gunk up, you'll still end up with higher nitrates if youre water changes are not bringing them down, or if there is no natural nitrate reduction going on. The accululation of debris can definalty help to add to nitrates, but if there is no bacteria converting the nitrates, than it's still there, regardless of wheather it came from a gunked up filter or just from normal nitrogen cycle taking place. The math doesn't have to add up, the science adds up just fine.