Are two-speed pumps worth it? HELP

[Ken and Laura]

I can't get a sreaight answer as to whether to get a single speed or a two-speed pump. I am replacing a dead ITT Marlow 1 HP Argonaut pump and I think a full-rated 3/4 HP whisperflo will work (emphasis on "I THINK")

I like the idea of a two speed so if I eventually get a chlorine generator I can keep a constant flow moving through the generator unit. Some folks have agreed this is a good approach, others say low speed won't circulate enough water to filter, other say I only need a two=speed if I have a spa - which I DO NOT have.

I'm getting desperate to get SOMETHING running before my water goes to heck - so any last minuter advice would be MUCH APPRECIATED!

Thanks

[cruzmisl]

How big is your pool? Pipe size? How many suction and return lines? What do you use to vacuum your pool?

[gwrace1]

I did the same research your doing when I had out AGP installed in early March. I have an SWG. The pool is 33' round with a 54" wall for a total of about 26000 gallons.

On low speed the pump consumes 3.8 amps at 120 volts. On high speed it consumes 10.8 Amps. It turns over an estimated 80 GPM on high and 35-40 GPM on low. I'm currently running the SWG for 12 hours each night with the SWG set on 40% with a CYA of 35-40 PPM and pump on low speed. I've noticed about a $35 jump in the monthly electrical bill since the install. The FC level holds consistently at 2.5 PPM and the water has been crystal clear since startup in early March. Water temps are running 85-95 degrees.

The high speed setting is nice when we want to run both the fountain and the pool skim or you want a really fast filtration cycle. We don't use a vacuam as I have a Pool Rover.

The pump is rated at 1.5 HP running with a 26" Pentair Sand Filter with Zeolite media.

[Ken and Laura]

Pool is 18x36 vinyl oval
-one skimmer and one main drain
-two returns in shallow ind
-All piping 1-1/2 inch plastic
-pump located about 40 feet from pool inlets

Filter:
3.1 SF sand rated at 4.7 to 6.1 GPS at 50 PSI

I can't find a pump curve for the dead ITT Marlow pump - but I figured out from part numbers on the impeller that it is a 1 HP. I'm only guessing a modern 3/4 HP will be sufficient without overpowering the filter

[CarlD]

I LOVE my 2-speed Hayward. I will NEVER own anything but a 2-speed pump. I run my solar panels with it on low all the time with no problem.

[Ken and Laura]

What are the specifics of your setup? In addition to the previous pool info I posted, I have about 22,000 gallons, manually vacuum through the skimmer, and dont have any other "water features" - just an oval pool.

I dont want to pay for something if its overkill

Thanks

[cruzmisl]

Using 50ft head as an average for most inground pools then a 3/4 HP 2 speed is more than enough. Whisperflo makes a 3/4 full rated and a 1HP uprated 2 speed which are the exact same pump. It will move 70gpm and probably half that on low speed. You'll save money everyday you have your pool open.

[CarlD]

I have a 1hp Hayward SuperPump, and a Hayward T-210 top-mounted sand filter--that uses 200# of sand. My pool is just under 20,000 gallons--19,200 and is a rectangular 40'x16' A/G with a 5 1/2 foot hopper-style deep end. See pics in the A/G pool gallery thread.

[mbar]

Carl, since I put in solar panels, I was thinking of going with a 2 speed pump (just burned out my pump) I now have a 1hp jacuzzi. With the solar panels, the return wasn't as strong as before the solar panels. When I turn off the panels the flow gets strong. The pump is next to the garage that the solar panels are on the roof of. The pipes go up about 10 ft. My sand filter is 200lb hayward. What would you suggest? I like to keep my pump running 24/7.

[eljefe281]

Warning! Answer from a not-yet-pool-owner!

Ken and Laura - How much more does the 2-speed pump cost than the single speed pump?

I assume that, if you chose the single speed pump, you would size it to perform the same as the 2-speed pump would at low speed.

Even without a spa, I would say that having the option of high speed operation would be desirable if you ever mess up the chemistry of your pool and want to circulate a lot of water quickly.