I was thinking that I could make my own sump very simply by having a siphon to the sump and a pump to return the water to the tank. In the sump, the water would first go through a coarse filter and then through some carbon. After that, it would go to a chamber with live rock, or bioballs and then the live rock plus a protein skimmer. Would this simple and cost-effective idea work? Any ideas are appreciated.