Not to contridict but when I researched skimmers I was told a prizm probably wouldn't do as well on a 75gallon. I then looked at the sea clone and it doesn't have a good reputation. I ended up putting out the money and getting a Berlin Turbo Hang-On. It cleans great and is worth the money. I also run an Emporer 400 with my tank. Between the 2 you are looking at I would go for the prizm over the bak-pak2.