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Pool Pump Size

Posted by USMCRET96 (My Page) on
Sat, Jul 2, 11 at 17:29

Hi, Bought a home that had a pool built in the late 1960's. It's a large rectangular pool that measures 20 ft x 40 ft with a diving board and slide. It is concrete and runs from 3-1/2 Ft for half the length before sloping down to 8 ft at the deep end.

The pump went bad and I replaced it with a 1-1/2 HP Hayward Super Pump C48L2N134B1 because the one that died was also 1-1/2 HP. The Filter is a Hayward S244T and the pipe size is 2" PVC.

Aside from a new filter pump, I�ve replaced the heater and had the skimmer basket replaced because the old basket was leaking.

I run the filter/pump about 8 hours every other day and the water does stay clear; however, I�m wondering if the pump is big enough because there is very little water movement around the skimmer and the surface of the water always seems to have leaves or dead critters floating on it.

Even when I vacuum the pool and have closed the main drain, there doesn�t seem to be very much water flow through the vacuum hose and every now and them, the pump loses the charge.

So again, is this 1-1/2 HP pump big enough? Or do I need a bigger pump and filter?

Follow-Up Postings:

RE: Pool Pump Size

You need the pump on every day.

A fair estimate of 75 GPM is what your system is moving, assuming there is little to no air and the filter's pressure gauge is functioning correctly and reading 18 PSI with a clean filter. As the filter captures dirt, the pressure will rise and the volume of water will be reduced.

Assuming the above is true, it will take about 7.5 hours for a complete turn of your pool's volume, which is 34,500 gallons. With most residential pools, one turn is the usual norm needed.

I would have expected 2 skimmers and a drain. Most builders used this configuration with pools built over 650 square feet.

If you remove the skimmer lid and look inside with the pump running, you should see ripples of water. If you see either nothing or a gentle whirlpool, it is likely the weir is missing.

The weir's purpose is to force the water being drawn in to come from near the surface, where the surface tension of the water will draw in debris. Without it, water is drawn into the skimmer from below the surface, reducing the skimmer's effectiveness.

You seem to be new to pool care. For a better understanding of what your pool's needs are to be kept clean and healthy, I urge you read the Pool School at for your sake and for those who may swim in your pool. It will help fill in the gaps you seem to have in caring for your pool.


RE: Pool Pump Size


Thanks for your quick response. If by 'weir' you mean that flap that should in in the skimmer (like the two skimmers in our Koi pond), then yes it is missing. I'll check with my local pool company about having one installed.

I'll also check the web site you provided and do some reading.

Again, thanks!


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