When I first started I had an Emperor 400 as my primary filter, but then I bought 100#'s of lr and disconnected the pump. If you get a dsb (deep sand bed) and 1-2 #'s of lr, that is all the filteration you'll need for the nitrogen cycle. You'll still need a skimmer or a refuge to export nutrients out of your water. Some people use the emporer without filter bags or anything just move some water around. There is even a post somewhere on this site, I forget which forum, where someone details their conversion on their emperor into a refuge. Do a seach...hth