i am building a sump. I have a 40 gallon bow front and I managed to fit a 20 gallon tank under my tank. What size pump would I need for my return?
What power heads are you using for flow? That kind of determines how much you will depend on the return lines to provide flow. In my nano I'm running two return pumps that are 25x my display volume. In my large tank I'm only running 8x my display volume. It also depends on what you want to do. If you will have a refugium I would keep to the lower side (8-10x display volume) for greater contact time for your macroalgae. Remember more volume often equals more noise depending on your overflow and drain system. As for brands....there are a lot of good pumps. I'm kind of fond of Sicce Syncra Silent pumps. Very dependable, quiet and easy to take apart to clean when needed.