Originally Posted by SpyderMike
the fish seem to be happy and healthy, should i just leave the nitrite lvls high to help "feed" the bacteria?
I don't think its normal to have a nitrite reading of 5 after six weeks of cycling. As you say the fish are fine, are you sure the nitrite test is accurate? Do you remember when the ammonia levels were first at 0 (where I'm assuming they have since remained)?
I wouldn't do a water change for the nitrite (if it really is 5), that may make it worse--unless the fish are stressed. The biological cycle has to establish itself naturally, the nitrobacter bacteria in this case have to multiply to handle the available food (nitrite) produced by the nitrosomonas bacteria, and you don't want to be removing them. As you say, better to leave them to fe the bacteria. I would recheck that nitrite.
As for nitrate, it is almost always present in a biologically established tank. Nitrates are produced by the nitrobacter, and then usd by the plants (if you have plants) and removed (kept in check) through the weekly water changes. Nitrates are only toxic to fish at high levels, most aquarists consider a nitrate reading above 40 to be dangerous, but if the system is balanced and you are doing regular (weekly) partial water changes, and don't overload the biological system with overfeeding, too many fish, dead fish, etc., you should never see nitrate problems.