Rehabbing an old pool -- Need recommendation for new pump & filter

[Bayside33]

Hi, great forum! I've been reading thread after thread the past few weeks and have found tons of helpful & useful information so far. Thanks for the great resource!

I need some guidance selecting and sizing new equipment for an existing pool. I recently purchased a home with an 20'x40' rectangular in-ground pool w/ auto cover. No exact measurements but I believe it is approximately 35,000 gallons. The pool is a steel wall, vinyl liner pool manufactured by Fox and was constructed in 1990.

I would like to replace the old Pentair 1/2 HP pump and sand filter. The original equipment looks horrible and I was told hasnt been in operation for 3 years. Here is what I have on the list so far:

Filter
Pump
Timeclock

I like the idea of running a pump at a slower speed for more hours per day, so I have selected a 2-speed pump. Doing some research online and quickly glancing at pump curves I think a 3/4 HP pump is a good fit.

More details on the existing piping: There are two skimmers, one main bottom drain, and two returns at the pool. The equipment is a good distance away from the pool, the longest pipe run is about 100 feet & the shortest run is about 70 feet. There is not much elevation change from the pool to the equipment pad, definitely less than 12". There are three 1-1/2" lines entering the equipment pad (2 skimmers + bottom drain) but only one 1-1/2" line from the equipment pad back to the pool. I don't know where this line tees off to the 2 returns. Having the single 1-1/2" return line back to the pool is one reason I didn't go with a larger pump.

- Is the 3/4 HP 2-speed pump a good choice for this pool?
- Is the filter I selected too large? I'm concerned about minimum flow rate through the filter when the pump is on low speed.
- Are there and other common items or accessories that are required to install this pump/filter? I'll do the new PVC piping myself with stuff from the local hardware store.
- Any different timeclock recommendations? Is the Intermatic linked above the best/easist way to enable 2-speed pump operation?

Once I have the new pump & filter installed, I plan to completely drain, clean, and refill.

Thanks!

 

[jblizzle]

Welcome to TFP!!!

That pump may infact be larger than you need, a Superflo 1HP 2-speed is smaller and cheaper to buy and run. I do not see any mention of a need for high flow rates.

You can not really go too large on a filter. There is no such thing as a minimum flow rate for filtration. In fact for the size of your pool, a 72 sqft might be better.

There is generally no need to have the pump change speeds on a schedule. You could just leave it on low speed and use a simple on/off timer. Then switch to high only when you need it (like for vacuuming, backwashing, etc).

You can not drain your pool if the liner is more a year or so old as it will shrink and not go back into shape. There is hardly ever a need to drain and refill a pool.

 

[sargent]

It is hard to find 2 speed 115 volt pumps, so that Whisperflo may be okay if you need a 115 volt pump, but if your old pump is 230 volt, you should go with a 1 hp 2 speed that is not a Whisperflo. As Jason said, it pumps more water than you need and would therefore be more expensive to run than, for instance, a Superflo.

 

[jblizzle]

Good point on the voltage differences.