Guys, I need help on building a sump, and I don't know how thick of a sheet of plastic, i should buy and how to run plumbing properly. how should i set up my baffles. I want a sump to be 14in h x 28in L x 15in w. So far what I know about sump is water goes down from the over flow and to the sump, then water runs to a protein skimmer, out, then run to a refugium, then to a return pump in the last baffle. Most people run with pvc pipes and return pipe must be installed with a check valve. oh one more thing, how do i cut plastic sheets?