Mag 18 (1800gph), mag9.5 (950gph).
readings are at 0 head. That's pushing straight out of the pump. The ft height is how many verticle feet (head height, see calculator that I posted) the pump could push up and by the time it got to the top of that run, the posted value is what would be coming out of the other end (at 21' with 3/4 fittings a mag 18 would be pushing 200gph, for example).
If you take your desired pump and enter the information into the calculator that I posted you'll find out how many GPH
will be coming out the end of the pipe.
Have you checked CaptiveReefs? I've had a hard time beating his prices on most items.
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