Hi, Essentially what I need is a pump that will pump 40 gallons of water per hour to a height of 8 feet. Ignoring pressure losses in the lines (for now) I used the bernouli equation to determine that I need a pressure change of 3.44 psi in my pump. I found these pumps that look suitable but all list a max head far lower than the 8 feet I need. http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=21414 I was thinking maybe just use one with a higher volume flow to compensate for the head loss. Maybe the 100 gph one? Is there a way to determine exactly what I need? Thanks!