The tanks are small, but there's 8 of them. That leads to a question: Do you see any "expansion" in your future, lol!? You certainly don't need anything like an Alita or even a Pondmaster. But if you see something bigger in your future with deeper tanks and more tanks, the smallest Alita would be my first suggestion. But if you see this as pretty much as big as it gets I, personally,wouldn't have any basis for recommending any of the smaller diaphragm-type pumps. In a nutshell, it usually pays to look down the road a bit since upgrading just downgrades your wallet.