Running pump low vs. high

[KarenNJ]

So I followed the recommendation to get a 2 speed pump. Everyone I speak to with pools has only a one speed pump and they run their pump about 6-8hrs a day. I was hoping to run my pump on low to save on electricity, but am I going to need to run the pump 24x7 if it is on low? How exactly does a 2 speed pump benefit me? Also, on high I am at 10psi. I see lots of movement in the water and everything appears to be running well (except I do seem to be getting air bubbles shooting out of the return every so often). On low the pump is only at 1psi. How much can it be doing at 1psi? The water seems to still have decent movement but how can I tell if it is enough?

 

[needsajet]

First off, you'll hear a lot of things about how people run their pools, but always remember that your pool is unique. Pools vary a ton because of shape, depth, wind, temperature, organic load, bather load, cleaner used, amount of brushing, etc.

On low speed, you're probably using (roughly) 1/4 as much electricity but still moving 1/2 as much water. Don't worry; it's a good decision! I run my pump on low for 8 hrs per day in full hot sun with lots of swimming happening. Others run them on low more hours for various reasons, but it's still good use of power. The amount you run your pump will depend on what you see working for you - that is, skimmed when you want it tidy, no cloudiness in the water, no algae showing up in corners with poor circulation. Adjusting your return jets to get the water slowly moving throughout the pool is also important, and you can observe over a few weeks as you adjust and get it the way you like it.

More here: Pool School - Determine Pump Run Time

 

[Jimrahbe]

On low the pump is only at 1psi. How much can it be doing at 1psi? The water seems to still have decent movement but how can I tell if it is enough?

K,

Most of the time my filter pressure is about 2 PSI and my pool works just fine... Filter pressure is really the amount of effort it takes to push water through your filter. So when the pump is running slow it takes very little effort and when the pump is running fast, it takes a lot more effort.

I see you have a SWCG.. this will require you to run your pump long enough to generate the amount of chlorine required by your pool. Normally this is more than enough time to keep the water thoroughly mixed and the surface clean. This is the real value of a 2-speed pump.. Let's say you need to run your pump for 8 hours to generate chlorine.. Running a single speed pump for 8 hours costs about four times more than to run your 2-speed pump on low for the same 8 hours. SWCG's generate the same amount of chlorine per hour no matter what the pump speed is.

I suspect your friends believe in the "turnover" myth where you must pump all the water in your pool through the filter so many times every day.. This is just not true..

Thanks for posting,

Jim R.

 

[Joshii]

K,

I suspect your friends believe in the "turnover" myth where you must pump all the water in your pool through the filter so many times every day.. This is just not true..

This applies equally to the full speed case as well though.

IMO, the real answer here for cost savings is that running the pump at low speed will move half as much water at one quarter the cost. So, even having to run it twice as long you're still saving half the energy. No matter how many turnovers or fractions of turnovers you're looking for.

 

[KarenNJ]

Thanks! I got a SWG rated for 40K gallons and mine is only 14K so hopefully it will convert the salt fast and I don't need to run the pump very long. My hubby was against the pool to begin with and if it ends up costing us hundreds a month just in electric he won't be very happy....