Is there a recommended size for sumps? Proportion to tank size? Or is it just make sure you have enough room for all of the necessary equipment? I'm looking into upgrading to a 240 long (96x24x24) and trying to figure out how big of a sump I'm gonna' need. I know I need enough room for a skimmer, 1-2 return pumps, heaters, and live rock, but is there anything else I need to make sure of with the size of the sump?