Reconfiguring Filter System and Converting to 2-Speed Pump


Mike S

I just went through my first year with a pool and thanks to this site it was much easier to take care of than I expected. I relied on liquid chlorine to chlorinate my pool. After a few weeks I had a pretty good handle on how much chlorine to add daily and was able to get by with testing a few times a week depending on the weather and our use.

The pool was built in the mid 90’s and the equipment has started to show its age. I added a booster pump for a Polaris cleaner and the main pump was dead when I opened the pool last May. I replaced it with a Hayward SP2607X10 1 HP single speed pump. The heater is less than 10 years old and seems to be in good shape. The DE filter (48sq ft) is original and is made of stainless steel. It is showing some rust on the outside and I am getting some DE in the pool, so I am guessing the grids have a tear in them somewhere. The valves have all seen better days and the lines have some minor leaks in them. It looks like they have been cut and reconfigured several times and there really isn’t any room to do anything with them.

I closed the pool last week and started thinking about some projects to do with it before next season. Looking at the price of the filter grids and given that the tank is showing some rust, I’ve decided to not throw any money into it and just get a new filter. I’m starting to do some research, but I am leaning towards a Pentair Quad DE 60 or 80. I’m also researching going with a SWG and am looking hard at the AutoPilot Digital although the Hayward systems and some of their automation options they offer are interesting. I’m wading through all of their models and trying to figure out how wife friendly going that route would be.

I’m also considering switching out the motor on my pump for a two speed motor. I have looked at Hayward pump curves and have done some rough head calculations using my existing filter. I generally get about 14PSI on my current filter and the pressure really never moves more than a 1 or 2 PSI. So at about 40 feet of head I think I am currently getting about 55 GPM. It sounds like my heater and a SWG would have a minimum flow rate. Is there a way to estimate my total head and flow rate assuming a new DE filter and a 2-speed pump running on low? When I look at the pump curves for the 2-speed version of my motor, the low speed flow rates varies by quite a bit over a narrow range of head.

My lines are all 1.5 –inch and I am just going to start fresh from the ground on up with new lines and valves when the time comes to install everything.

Thanks for any advice.


TFP Expert
LifeTime Supporter
May 3, 2007
Pleasanton, CA
A two speed pump on low speed will produce about 1/2 the flow rate of high speed. So if you are getting about 55 GPM on high, you would get around 27 GPM on low. But that should be enough for the SWG but probably not the heater. But it might not be a good idea to run the heater on low speed anyway since the temperature rise of the water coming out of the heater would be about twice that of high speed.

Mike S

Thanks Mark,

That was simple enough. To be hones we didn't run our heater once this year. When we need to run it I guess that I could always just run the pump on high. I'll have to double check my manual for the flow requirements on my heater.

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