I have used CPR BakPaks for a long time now and I think they are a great skimmer for smaller tanks. You have to option to put some bio filtration in it if you want or just use it as a skimmer. The only problem is that you do have to clean out the venturi and that is a minor pain and for some reason the stupid Rio pump doesn't want to come back on sometimes. My next skimmer will be the AquaC Remora.