Is my sand filter sized right?

[CarlD]

Isn't this a 325# sand filter? If so, there is NO WAY it's not sufficient for an 18,000 gallon pool. You just may have the wrong pump.

I think it's really time to explore your pool chemistry.

[TheGoose]

What pump do I need then?

[CarlD]

I can't think this late at night, but I find it hard to believe that ANY 1hp pump made is straining THIS filter! I'm thinking it's a chemistry or plumbing problem, not a filter/pump sizing problem. Fellow mods and senior contributors?

[PoolDoc]

Carl, the Whisperflo is a more efficient pump than average, so a 1HP WhisperFlo moves more water than a 1HP SuperPump. Plus, the Whisperflo is often sold full-rate, so you are comparing a 1HP full rate Whisperflo with 1HP uprate (=3/4HP full rate) SuperPump.

The give-away that this is almost certainly the problem is early in the thread, when Goose comments that he's

almost certain than when I backwash I am losing sand, and I noticed that when I changed the sand that the level was a little low.

Flow is high enough to push dirt through sand BEFORE it gets high enough to blow sand out of the filter during backwash.

Goose, since budget isn't a big issue, I'd recommend the following changes:

1. Replace the TA60 with a TA100 filter. That will allow flows up to 70 GPM without overloading your filter. However, better clarity and longer filter runs will come with LOWER flows.
2. Replace your motor with a 2 speed 1HP motor . . . and run on low almost all the time.

If you want a timer, Intermatic has one that will switch speeds. But, using a toggle switch may be all you need. With a 1HP Whisperflo and a TA100 you'll be running 20 - 30 GPM on low speed! You'll probably need high only to backwash and vacuum.

Alternatively, if you want optimize things to the max, you can go with a Pentair Intelliflo, which is a 2HP Whisperflo with special motor and variable speed drive. I believe it comes with a built-in timer.

HOWEVER, please send photos of your piping at the the pump and filter before you start, and let me or Mark (mas985) look at it before you do. There are a number of piping practices that many pool builders follow that are HORRENDOUSLY bad, hydraulically. Correcting these can greatly improve your efficiency.

Here are links:
2 speed motor (A1 Pool Parts)
WhisperFlo pump
Intelliflo (Whisperflo w/ VFD)
Tagelus filters

[TheGoose]

Thank you very much for the info. My pump/tank set-up is pretty straight forward. Two lines coming up from the pool, into a jandy 3-way valve. One from the skimmers, one from the bottom drain. Discharge from pump straight to tank, then tank discharged back to pool with a 1" line coming off for the booster polaris pump. The piping is all 2" on the inlet, but I believe it goes down to 1.5" on the discharge to the tank. Tank discharge I think goes back to 2" at the ground level where it goes directly to the return jets.

I installed the complete pump/tank combo a few years ago myself along with the electrical components so I'm pretty competent in that area.

Thanks for all your advice. I'm definitely thinking about the dual speed. What is your opinion on going back to DE as opposed to sand? I don't mind the extra work if it means my water stays clearer.

[PoolDoc]

DE will give you clearer water, and will reduce your pools tendency to get algae. BUT, if you do get algae, cleaning up is MUCH easier with a sand filter -- one algae episode can result in as much DE use as you'd otherwise use in a year. So, I don't recommend DE for folks who tend to neglect their pool every so often.

[TheGoose]

All great advice. I think I'm gonna leave my pump/tank alone and go with the 2-speed motor on my existing pump.