Questions about Return Pumps

[JRBear5658]

if so with the pipe laying flat on the tank floor would I still calculate the head by how long the pipe is going to be?

My tank design set up and plans are all at:

http://www.reeffrontiers.com/forums/showthread.php?t=55450

 

[jrgilles]

My understanding for calculating head pressure is:

1' head pressure for each verticle foot.
1' head pressure for each 90 deg bend.

That is way oversimplified, but makes me think the amount of resistance from a 4' horizontal run is much much smaller than the resistance from 1' vertical. Negligible maybe, but you could add in a 1/4 of 1/2' head pressure for it