Thanks everyone for all the help. i have just got my new 72 bowfront reef ready tank and want to start puting it together. i want to built a sump/refugium. What size tank should i use? (in gallons). I curently have a 20g and 10g x 2. will any of them be good? i will apreciate all sugestions. I plan to use a Mag Drive 9.5 as a return pump.