I personaly have never liked the wet dry system. Maybe because i am just plumbing challanged. :notsure: I have a 45 gal FOWLR that has been set up for 3 years. I have a 3 inch sand bed and about 40lbs of live rock. the only filter i have is a CPR hang on back refugium. I have never had a protein skimmer, and i only do a 5 gall water change every 2 weeks. The live contents, include, a hawkfish, 2 cadinals, bi-color, yellow gobby, 2 pepermint shrimps, a 4 year old blood shrimp, about 20 hermits and snails. Also got a blue knuckle hermit, he jumped out of my 125 reef, found him walkin along floor, so i dropped him in FOWLR, guess he didnt like reef life. :thinking:
Your design for your Sump is a good one. I have made several for my friends. Please stay away from bio-balls.
Good luck with your FOWLR.