Determining Optimal Variable Pump Speed

  • Last Post 22 May 2023
Smills posted this 21 May 2023

How do you detemine the optimal variable spped for a pool.  I am aware of the various pump curves and the presure versus flow rate charts.  Howver, the size of the piping, the length of the piping runs and type of filter will have to be determined or estimated to get in the ballpark range of motor speed.  I typically leave the pump on 24/7 since it has a Pentair Intellichem control systen for PH and ORP control.  The pool volume is 17,500 gallons.

Any advise would be appreciated.


InyoRich posted this 22 May 2023

The basic rule of thumb is that the pool water should turn over (go through the filter) at least once per day, so you can use your flow charts and head measurements to get a ballpark idea as to how long that would take.  The bottom line is actually whatever your pool needs should be what you do.  We have seen some pools run their pump as little as 2 hours a day and look as perfectly as pools with pumps running 24/7/365.

With your variable-speed pump, you should be able to program 3 or more cycles per day.  To save on your electric bill, we would recommend running it less than all day.  If you like the look of your pool operating, maybe run it in the morning and turn it off mid-day and run it again at dusk or at night.  If you want to run it all day and night - go for it!  You can turn the pump down to a low enough speed that it can be done economically.

Running it less will help your pH since those pretty ripples on the surface contribute to pH rise.  Not running it at night may help reduce overnight heat loss a little.  We would recommend running it during the day to help maintain your sanitizer levels, as that is when the sun can eat up the chlorine and cause sanitation issues and algae growth.


At the end of the day, if you’re consciously spending more money on a variable-speed pump, you should reap the long-term benefits. With our general rules, guidelines, and tips, you will.