I have one, its in my closet, it seems do a much better job there than when it was hanging on my tank making it look like a big vat of alka seltzer, whist barely collecting any waste at all, make sure it has the recent impeller, its not that recent, I got mine when it first came out, and it had an 8 blade impeller I think, they replaced with one with more blades, it helped, but not by much, the design is all wrong, the reaction chamber is way way too small, and the pump is crap, you set it low enough to where you get soo contact time, and close to a dry foam, then a few hours later, there is no flow coming out of the return, it was a good basic idea, but it needs some major tweaking, from the factory, you really cant modify it much,aside from getting rid of it and buying something better. I bought the prizm to replace an cpr bakpak mark I prototype, which can be finicky, but not near to the degree of the prizm, I'm gonna break down eventually and buy a remora