What is the cause of no ammonia but lots of nitrite in a reef tank?

Answer by  Tank (539)

A large buildup of nitrite is probably caused by detrius and food trapped in crushed coral substrate. If you have crushed coral replace it with live sand. That should get rid of that problem. Also performing a 25% water change is a very good idea. Cleaning the filter media will help as well.

Answer by  SaltWaterLover (48)

It could be a number of reasons but the two that jump out at me are either the ammonia has already been converted to nitrite via the tank cycling. The other often overlooked but quite common culprit is that your home water source is already high in nitrites.

Answer by  SunnyStars (836)

Your tank may be "cycling". Change 25% of the water, replace water with dechlorinated saltwater that is the correct temperature and salinity. Add a liquid bacteria starter. Use a water quality test kit at least once a week. Nitrites and ammonia should always read 0 or else your fish can die. Remove any fish until your reef tank is cycled.