Split drain or split return?

[scherzo]

@Anthony - eek! at least I had the forethought to run it externally.. will that help? I can also easily change it out with something else. - Do you have anything kicking around. (BTW.. The skimmer I have is your old Euroreef RS100 .. bought from someone who bought it from you!!)

As for sump design. I did check out Melev's Reef for designs. I'm actually using his 80 gallon design (slightly modified) because I need (want) to maximize my refugium section since my sump will be viewable. I will be able to have slow flow through the refugium if I want.

I also have an unfortunate size for a sump (48 X 16 X 24.5 H) so I have a strange layout. My refugium section will be (36 X 12 X 24 H) - about 45 gallons.