When I think of head pressure I think of pumping up.. so when the pump data says it has 21 ft of head pressure does that mean horizontal or vertical or both?
I will only be going vertically 6 or 7 ft but horizontal length of 30 feet. What should I look for in a pump?
Not sure how to do all that but that's what the internet is for.
Calculate your needed flow rate, run the friction loss calcs on the piping, and see where your head pressure is. If its not acceptable, jump to the next size pipe and repeate the process. Make sure you are looking at the pumps flow curve and not thinking it does the advertised volume at max head pressure.
Dan head pressure is what the pump can lift straight up above the water column. If the pump has a 1 in outlet it can lift water 21 feet in that dia pipe. It does not translate to horizontal or gpm as there is to many variables. If the pump is a 1000 gph pump that doesnt mean it will produce that at 21 feet of lift. A 1000 gpm pump is the water it can lift or move just above the surface of the water. The higher the lift or longer the pipe will drop accordingly.
Yea, most pumps that are called like a 1000 gph pump can only pump that at 0 head. Look for a pump that has a curve or a chart that will tell you how many gallons per minute or hour it will pump at various heights and then pretend your horizontal run is a could extra feet of height (and if you want to get a bit extra out of a pump, up size the plumbing a bit.)
So you are looking for a pump that will deliver some given volume (at least the volume of your fish tank) at say 9 or 10 feet of head. Remember, spend a bit extra on an energy efficient pump and you will save money on electricity in the long run.