Ok I had 125gallon about 5 years ago. Had to move and sold the break down to my LFS. I bought a BioCube 16 about 2 months ago. Just something to keep in the night stand. Everything went great cycled it in about 3 weeks. Now my ammonia is sitting at .5ppm and nitrites are at 1ppm with zero nitrates. Currently have some zoas, green star polyps, a mushroom and 1 black ice clown. Been that way for 2 weeks and levels are still holding the same. Need to get things down a bit. Done 4 50% water changes, cleaned sand bed and changed filter material. New to the nano world any suggestions?