40,000 Gallon Pool, old pump and sand filter - need recommendation for new.

[coloexposures]

40,000G IG pool with 20 feet of head (1 skimmer close to pump). Rarely pull water from the drain - but, that would add 8 feet of head. Currently have a 1HP single speed Hayward Super II pump and an old sand filter. Want to save on electricity this summer so going to cut down on run-time on pump. Don't have a spa or water features. Ready to buy an entire new system - pump and filter - because old filter is leaking, and so is impeller / time for new. Thinking of going with cartridge instead of sand. Don't have 220V to the pool house.

Pool store is trying to sell me a 2HP Hayward (SP3015X20AZ) with a 400 Sq.ft cartridge filter(C5025). They said the pool is too large for a 2-speed or Variable speed pump. Any quick advice? Thank you!

 

[duraleigh]

The correct size pump for that pool would be somewhere around 1.5 HP. I personally favor a 2-speed but VS, 2-speed or single speed has to be your call.

Most people stay with the same type filtration they are familiar with. Why do you want to change from sand to a cart?

 

[coloexposures]

Thinking of changing from sand to cartridge for two reasons:
1. Easy of use, less valves to deal with, longer filter cycles.
2. No backwashing - we are having some erosion issues on our property from backwashing over the years, and also discoloration of our asphalt driveway.

 

[JVTrain]

I'd get a 2 speed or a VS, skip the single speed. You'll have flexibility with the pump speed options and power savings when running on low speed. 1.5 HP sounds good. I can't think of a reason at all to by a single speed pump these days. If you get a VS pump, opt for some surge protection as they are more sensitive to power outages and brown outs. Go as large as you can with the filter for less frequent cleanings and longer filter life as a result (cleaning wears out filters more than normal usage). 400 sq ft would be large enough.

 

[sargent]

If you are going to stick with 115 volts for the motor, you are stuck with either a single speed pump or you could go to a Pentair Whisperflow 2 speed pump, either the 3/4 hp full rated (WFDS-3) or the 1 hp up-rated (WFDS-24). Those pumps, on high speed, will not quite have the flow of your Hayward Super II pump (approximately 58 gpm vs 62 gpm vs 65 gpm for the 2hp super II based on plumbing curve A), and on low speed the flow will be much less (approximately 29 gpm). Replacing the sand filter with a cartridge filter will lessen the head, so the flow would go up some due to that.

The advantage of the two-speed is that the energy is about 1/4 of that of the single speed, assuming the same run time. Since the flow is around half, you may want to double the run time, so you end up using around half the energy. Variable speed pumps are even more efficient, but due to their increased initial cost, they may not make economic sense unless you have high electricity rates.

If you were willing to run 230 volts to your pump house, you would have more options for two speed or variable speed pumps.

For the cartridge filter, the C5025 would be large enough, but larger is okay too.