I myself am not a fan of this method, but it works! I like to have a small sand bed, about 1/2"-1". For nitrate removal, you should get a deep sand bed. A deep sand bed of about 1 foot would help nitrate removal. With it, you could make tunnels for fish to go in with pvc pipe, giving the illusion of a fish swimming into the sand. There is a lot of science going into the reason for this nitrate removal system. You could also hook up a deep sand bed in a bucket to your main tank. Overall, a good idea for nitrate removal.