My first nano tank (7.1 gallon Landen) had really bad diatom issues the first month, but it gradually disappeared as the tank "seasoned." I added some amano shrimp, but I really think the (accidental from a plant from the LFS) snails did a better job. YMMV. Try using a plastic fork from your LFFS (local fast food shop, lol) and twirling the diatom mass like spaghetti. Works well!