Can SWG run on low pump speed?

Maestro

Silver Supporter
Jul 21, 2015
135
Cape May Court House, NJ
Now that my pool is about a year old, I'm doing some upgrades that my original PB should have told me about but didn't. My single-speed pump is a bit noisier in the daytime than I like (plus I've read here that a 2-speed pump is more energy-efficient), so I'm going to swap it out for a Hayward 2-speed. My plan is to run it on the low speed for about 12 hours a day (double the time that I'm doing now) and only use the high speed when I'm adding chemicals. My current pump is 1.5 hp, and the new one will be 2 hp.

I also want to have an SWG installed. I read on this site today that it is best to run them during the daytime when the sun is actively dissolving whatever chlorine is in the water (makes sense). The new PB is going to install a Hayward system good for a 40K gallon pool and is rated to generate 1.4 lbs/day.

Does it make sense to plan on running the pump at low speed all day? Will that affect the efficiency of the SWG? I don't want to get this done only to find out that I have to run the pump at high speed during the prime part of the day when I want to be swimming - it will be even noisier than it is now! If that's an issue, will it work to run the pump at high speed during the night and on low during the day?

(if it makes a difference, I have a retractable cover that I usually close each night to retain heat and prevent evaporation.)
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,531
Tucson
Each system is different. It should be possible to run at the low speed, but you can't be absolutely sure. I switched from a 2hp Superpump to a 3hp VS pump, and found that I need about 1400rpm to reliably activate the flow switch on my SWG. Others can run at 1000 or 1100 rpm. It just depends on the plumbing of the system.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,824
Pleasanton, CA
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Does it make sense to plan on running the pump at low speed all day?
Not to me. Even 12 hours is too much in my book. I run mine on low speed for about 3-4 hours but that is only for solar. Without solar, I run on high speed for only an hour a day and that is for the cleaner.
 

Maestro

Silver Supporter
Jul 21, 2015
135
Cape May Court House, NJ
Not to me. Even 12 hours is too much in my book. I run mine on low speed for about 3-4 hours but that is only for solar. Without solar, I run on high speed for only an hour a day and that is for the cleaner.
I actually have no idea how long I'll have to run the pump – 12 hours was just a guess. Right now I'm running a 1.5 hp pump for 3 hours at night and 3 hours in the afternoon (with no SWG of course). There's a lot of variables that will determine how long the new setup will need to run every day.

I just wanted to know if others out there have found it possible to operate an SWG with a pump running on low speed, and if that somehow affects the efficiency of the SWG. Apparently it works fine for some and not so much for others. I hope I'm one of the ones it works for – wish me luck, everybody!
 

ping

TFP Expert
LifeTime Supporter
Jun 24, 2011
3,138
Long Beach, CA
The Hayward SWG's can operate at some of the lowest flows of all SWG's. Most 2-speed pump setups have zero problems for the Hayward SWG's. I have never had a flow issue with my Hayward SWG and I run it 90% of the time on low speed.
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,531
Tucson
The output of a SWG is unaffected by the pump speed, as long as the flow is sufficient to activate the flow switch. With a Hayward T-15 cell you will probably be able to produce enough chlorine in a couple or three hours a day if set at 100%. I prefer running at a lower setting and a bit longer. That allows me to adjust my FC level at the turn of a knob. If you run SWG at full output you need to increase run time instead of just turning the SWG up.
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,531
Tucson
As others said, it depends. Low speed works fine for my SWG, but if the solar turns on, SWG has no flow.
When your solar turns on your pump should go to high speed, problem solved. Since you have all Pentair equipment, the SolarTouch should be able to control the pump speed. I have SolarTouch and it communicates with my Pentair Intelliflow VS pump.
 

flipr

LifeTime Supporter
Aug 20, 2015
129
Punta Gorda, FL (SW FL)
When your solar turns on your pump should go to high speed, problem solved. Since you have all Pentair equipment, the SolarTouch should be able to control the pump speed. I have SolarTouch and it communicates with my Pentair Intelliflow VS pump.
That is true for VS Pentairs, but Whisperflo 2 speed can't be controlled by Solartouch, so Pentair told me