need some advice

[va_reefer]

Hi!

Am trying to figure out what this means....I have a basic idea, however, not sure if it is correct....

I am looking at getting the Rio Plus 2500 - 748 gph to act as a return from sump to a 75 gallon.
RIO states that "Max Head" is 10 feet.....is that the height it can push water vertically back into the tank? I wonder how this effects the gph? the total height of the tank is about 40 inches approx.

Thanks!

Va_reefer