What size a pump do I need?

Apr 29, 2017
Calgary, Alberta
I need a new pump. I can't identify the pump (its 30years old) to find the flow rate. The old motor is 1/2 hp single speed 115v.

I have gone online to try to calculate feet of head but the result seems high; 90ft

this is the data i do have:
-14 x 28 inground 15000gallons
-sand filter spec max 50 psi, 75gpm
-skimmer max 30 gpm
-estimated 42 feet of 1.5 inch pcv pipe with maybe 10 90 degree elbows
-no spa just pool
-7 to 8 feet max depth


Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
Houston, Texas
Re: What size a pump do I need?

You should be just fine with a basic 2 speed 1hp pump to circulate and filter water. Use low speed for filtering and circulation and high speed to vacuum. If you decide you want to add automation and water features to your set up then a variable speed pump would be the way to go.
Apr 29, 2017
Calgary, Alberta

Ended up getting a hayward maxflo vs pump. Arrived Thursday. Had to upgrade the pool house electrical to change to a 230 Volt motor. Installed the plumbing and wired in the pump. Did not have to buy a new 230V timer as the pump comes equipped with a digital programmable interface.

Loving it so far (ok, its been one day). The ability to adjust the flow to my needs is fantastic. The rotating interface is a great feature as the pump could only be orientated one way. It wasn't cheap but I probably shouldn't skimp on a pump.

Next issue, dripping heater fitting gaskets...we will see if i can source parts for another 30 year old part.
May 29, 2017
Sorry late, new here but in case someone else sees this.. you could have went with Pentair Superflo VS Pump. This pump can be wired 220V or 115V. Maxflo is great pump and glad it's working for You!
Apr 29, 2017
Calgary, Alberta
I did consider a 115 volt pump but preferred the lower current spike of each field when the pump starts up and primes. The parts for the electrical upgrade only cost $100 and the 30 year old fuse panel is now a breaker panel.