Have been battling high nitrates for about four months now. After cleaning out the seachem matrix in the sump. Doing 150 gallon (15%) water changes every week. Changing out floss pads every two days and running an aquaripure denitrator, two Aqua c ev-1000 skimmers a uv
starlllizer and multiple other options. I finally bought two new nitrate test. Both seachem. API was testing 60-80 no matter what and the seachem is testing 20-30. I currently am waiting on a salifert test to come in As well. I really need to be at 20ppm considering the stocking list I have so hopefully the salifert matches the seachem.