My skimmer calls for a 400-450 gph pump. That doesn’t seem to be a common size...
I also need to be able to connect to a 5/8” barb fitting.
So...I’m wondering if I get a little bit larger gph pump, could I use one of these adapters pictured below? And would it reduce the pump gph a little?
My next question is about these danner mag drive pumps. The mag 3 is advertised as 350 gph. The chart on danners website shows the mag 3 at 420 gph at 1’ head. Why the difference? Am I missing something?

I also need to be able to connect to a 5/8” barb fitting.
So...I’m wondering if I get a little bit larger gph pump, could I use one of these adapters pictured below? And would it reduce the pump gph a little?
My next question is about these danner mag drive pumps. The mag 3 is advertised as 350 gph. The chart on danners website shows the mag 3 at 420 gph at 1’ head. Why the difference? Am I missing something?
