Young Macdonald's Farm Ammonia Ammonia is produced in the systems by the metabolism of the fish and is also produced by the decomposition of the fish wastes and uneaten feed. This is one reason why solid wastes and uneaten feed should be removed as quickly and completely as possible. Ammonia is not as big a problem as once thought, first of all the part of the biofilter that reduces ammonia is the most consistent part of the biofilter and is the first to start-up. Secondly ammonia comes in two forms NH3 (toxic) and NH4 (non-toxic), so in your test kit your readings will be the total of both forms. The good news is, pH values near neutral percentage of toxic ammonia is very low. At pH levels of 7-7.5 total ammonia values 6ppm seem to cause few problems, especially if oxygen is in good order. It is not uncommon to see systems where ammonia levels of 20 ppm were present with the fish showing no ill effects. Aquaculturists don?t recommend this level and for the most part typical systems have seemed to produce ammonia levels of 1.5 to 2.0 ppm under stable operating conditions. Ammonia produced in the system increases as the feeding rate goes up or as the protein content of the feed increases. Since as your fish grow you will be increasing the amount of feed into the system the biofilter must be given an opportunity to adjust to these increases gradually to be able to assimilate the additional ammonia this practice produces. As long as you do not exceed the amount of ammonia that your biofilter is capable of removing, it will adjust to each new level in time.ement NOTE: SEE - Remote water quality management