Biocenosis baskets actually remove ammonia better then nitrate. It will tackle both but it's more effective and efficient to use them as the soul mode of biological filtration. Once they are working you remove as much of the other biomedia as you can and let them do their thing. Or if in a sump put the biocenosis baskets before other bio media so they get first crack at the ammonia using it completely so nothing is left but clean water. I have other filtration in with the biocenosis baskets and that will be the next step in my testing, removing those filters. Current testing shows no ammonia, nitrite or nitrate in the tanks where the baskets are used even after 6 weeks. Stocking varies from tank to tank as does feeding but all test the same, undetectable readings on api liquid tests.