Does anyone have any experience with the E-Heim 2227 or 2229 wet dry filters? These are canister filters that alternately empty and fill to provide a wet dry filter environment. They look appealing to me but I am a bit leery for what reason I don't know. I don't plan on keeping inverts, just a small fish population. My other option is to build my own wet/dry or refugium but I am having trouble understanding exactly what the difference is between these two systems, they both appear the same to me. I know that the refugium contains live rock and special algae but I have seen these placed into wet dry sumps as well and can't help but think this would be the best of both worlds so to speak. I think I would enjoy the process of building my own but the E-Heim seems like such an perfect fit for my apartment.