Overflow boxes and head calcs

[john0087]

I am finalizing the plans for my sump and I have a couple of questions about overflow boxes and my head calcs.

I am planning on using a CPR CS50 overflow box. This is rated at 300gph. Is this the max flow of does it mean that is siphons at a constant 300gph?

I plan on using 2 mag 5’s for my return pumps. I figure that my head is about 7’ 48” for the tank and stand + 36” for 3 90deg bends in the return U tube that I plan to use. The mag is rated at 125gph at this head height, giving me a total flow of 250gph.

Is this all correct?

Thanks

[MACATUA]

That is max flow.

[melosu58]

Moved to General Hardware and equipment discussion.