Okay 180 about 6 feet head full reef unfortunately I do not have room for an external so it has to be an in water, a little extra gph is okay I'll run phosban/carbon off of it any suggestions? Thanks
mag 12 / mag 18
Skimmerwhisper and a few others said you would want to keep your return about 3 to 4 times the rating of your skimmer. Unless you have an external pressure rated pump you should not try to get flow out of your return pump is that way I understood it.
I have 2-180G's. I run a Mag 18 (Highly Suggested) and a Gen-X PCX-40 External. I prefer the Mag pump. A Mag 12 should be ok but is on the lower end of the PSI to get a moderate flow @ 6ft minimum head.