Variable Speed Pump Help


New member
Mar 27, 2018
Phoenix, AZ

I just recently purchased a new pump, and due to AZ law, only variable speed pumps can be installed now. I have never used one before, and I have only worked with single speed pumps. I am trying to figure out the best way to calibrate it. My pool is about 30,000 gallons. The rule of thumb I have always been told her in AZ, is to make sure the pool pump is running 1 hour per every 10 degrees. I currently have had the 1.5 HP single speed pump running for 9 hours. I have strayed away from that rule in the past, and my pool turned pretty quickly. This is why I am concerned with how it was calibrated.

I have read online that a single speed pump runs at 3450 RPM. So I had been running 3450RPM for 9 hours each night.

The pool guy calibrated the pump to run at about 2600RPM for 5 hours, and 1500RPM for 4 hours. This doesn't seem to make sense to me. I am really worried about the pool going bad if I don't get this solved/understood.

What I am thinking might be better, is to run the pool at 3450RPM like before for 5 hours. And then run the pool half that at 1725RPM for 8 hours. (double the time due to half the speed). I think this would give me the same cleaning power but also give me savings as well.

Any thoughts or suggestions would be greatly appreciated as I have found myself frustrated with this.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

Welcome to TFP... a great place to find the answers to all your "Why do I believe pool store myths?" questions... :shark:

If your pool turns green when you cut back on your pump run time, that is a chemical issue and not a pump, filter, or run time issue...

Each pool is a little different... But you generally run a pump for three reasons:

1. To keep surface debris moving and being pushed into the skimmers. The more debris the more often you need to run the pump.

2. If you have a Salt Water Chlorine Generator (SWCG) you'll need to run it long enough to generate the amount of chlorine needed.

3. To circulate the water to ensure the chlorine is effectively distributed throughout the pool. Two or three hours per day is all that is needed for this to happen in most pools.

The rule of thumb about 1 hour per degree is just an old pool store myth..

The whole purpose of having a VS pump is so that you can run your pump slowly as possible and still skim the water... Because I have a SWCG, I run my pump 24/7, but most of the time it is only running at 1200 rpm, which costs me less than $20 bucks a month.

Of course it is your pool and you can run at whatever speed you want, but the speeds that your "pool guy" selected (2600 and 1500 rpm) look pretty good to me.

I can't think of any reason that your pump needs to be running at 3450.. ever..

Let us know if you are interested in what is most likely causing your pool to turn green and we will be glad to point you in the right direction.

Thanks for posting,

Jim R.


Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
Fletcher, OK
Welcome to TFP :)

You will soon see that the 2 things you are talking about are not tied together :)

A couple questions first.

1. How do you chlorinate your pool
2. do you have a FAS DPD test kit
3. What type pool filter do you have

A VSP pump will need to run the lowest setting and the least amount of time to keep your pool clear/clean.. What does that mean?? It means the clarity of the water you want in your pool, some people like a clearer pool so they run a little longer, a good place to start is 4 hours and go from there..

That might look something like this

3450 RPM 5 minutes (just to get a good prime)
1725 RPM 1 hour (this can be adjusted up or down to get most of your leaves or bugs out fast)
1000 RPM 3 hours

Your pool going bad (green) is tied to chlorine, nothing else.. If you keep you FC level in line with your CYA it will be just fine.. Now your asking yourself what I am balbbering on about, all the "pool" people have said to keep FC at 3 or 4, right :)

Here is a chart on what FC you need in your pool depending on your CYA.. [FC/CYA][/FC/CYA]

Please spend some time going through pool school and you will soon see it is really easy to keep your pool from turning bad...
Pool School - Getting Started

I hope this helps :)


Gold Supporter
May 18, 2016
West Bloomfield, MI
Another thing to keep in mind is that the energy consumption isn't linear in regard to RPM: running your pump at half the speed consumes considerably less than half the energy.

You can experiment with speeds to determine the lowest speed that will provide sufficient skimming, and then how long/often you need to run at that speed. Set the circulation to a nice quiet, slow speed and watch your electric bill plummet!


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
FL panhandle
That's true, running a pump at half the speed moves half the water but consumes less than a quarter of the electricity.


Silver Supporter
Aug 28, 2012
Houston, TX
sahal, welcome

Look at the bottom of everyone's post and you'll see their pool information. pls complete this bc it will help people to provide you w more accurate numbers.

In general, 3450 rpm mostly makes your energy provider higher profits and you w less disposable income. do you have a spa/SWCG, water features, type of pool cleaner, etc? lots of things can dictate rpm speed, but the question is for how long ??