I usually use large sumps the last one I built is for a 230g tank and it is 48"x20"x20" and has baffles for mud bed with macro algae and plant lighting, has other baffles for skimmer intake, and skimmer return and for seperate return pump. Also has holes for CaReactor in the future if it gets turned into a reef, I like high flow tanks and this lets me use close to 4000gph of total flow on this tank.