pressurized external pump question

[md14fish]

Was wondering if some one knew if there is much head loss when using pressure rated external pumps. For example- if each of my overflows can handle 600 gallons per hour would a pump rated 1200 gal per hour suffice or would I lose flow if the water is moving 12 feet back to tank.

[reef2]

12 feet is alot of head to push water. yes u will lose gph the farther u push water. u will need a big pump to move 1200 gph up 12'. use this calc to help u out.
http://reefcentral.com/calc/hlc2.php

[ReefWreak]

You would lose flow, just less with a pressure rated pump than with a non-pressure rated pump. You'll lose head for every foot of vertical distance, every 90 degree elbow, every foot of horizontal piping, just different amounts for each section described above. You shouldn't have a problem running a 1200gph pump on a 1200gph draining system, as to my knowledge the pumps can only lose flow not gain it, i.e. never pump more than the maximum of 1200gph.