High nitrate only!

[Myka]

Ammonia is eaten up in the system by the bacteria as quickly as it is produced so there is never enough ammonia to be read on a typical hobbyists' test kit. Same with nitrite. If you used a very expensive, very accurate, very sensitive ammonia test you could get an ammonia reading in pretty much any marine body of water. This also happens with nitrate and phosphate...both can be eaten up by algae so quickly that there is not enough left in the water column for typical hobbyist test kits to detect.

Originally Posted by Wayne

The only way to get rid of nitrates is with water changes, NP pellets, Zeo or Vodka dosing (or other similar bateria eating nitrate means)

That's not entirely true, the best natural denitrator is live rock. The anaerobic bacteria within the rock will convert nitrate to nitrogen gas.