I'm looking to add a 55G or larger sump to my tank and I've read pro and con for skimmer-return-fuge and also skimmer-fuge-return sump designs, but I'd like to know what the reefers who have been using sumps have to say about order preference and why--advice? Also, I would like to add a frag section or rack to the sump design so any thoughts on where this would best go in the design would be greatly appreciated too. Thanks!!