I would like to add more fish to my 80 gallon tank. My nitrites are high (3-5ppm) and I think it's due to the filter intake being so high up above the sand it doesn't take in poop. I was thinking a catfish would be good to eat that stuff or maybe a power head to stir it up, but I'm under the impression those create current side to side. I have 2 eheim filters. the pro 2 has biomedia, substrate and carbon (in that order)and the eheim 213 canister has bio media, filter floss (i ran out of substrate) and a bunch of carbon in an attempt to cut down the nitrites. I tried water changes but they do not do much in reducing the levels.
nitrates are at 20ppm
hardness is about 100 to 150 (GH) ppm
alkalinity (KH) is 40-60ppm
pH is 6.8 to 7.2
