I've had tanks for years but all freshwater. I've been wanting to set up a saltwater tank for the past few years but really have never pursued it. I want to start small and was thinking of getting an all in one, but one day i'd like to have a bigger tank and want to go through the steps now of setting up that style tank. I never thought of setting up just a 20 gal salt water tank that wasn't an AIO. Is it worth the time and effort? Do they sell 20gals with overflows? What is the best route to follow if I really want to set up a tank?