Confused by pump size calculation

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Athlon646464

Athlon646464

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Jun 21, 2010
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Uxbridge, MA
Hello - I just can't get my head around the pump sizing info on the site here. I'm ready to order a Pentair CCP520 cartridge filter (520 sq. ft.) , but I don't want to attach it to the wrong pump. If my current pump will work with it that would be great, if not I'll get a new one.

I have a 16 x 32 20,000 gallon in ground pool
2" plumbing
3/4 HP Hayward single speed pump
Hayward sand filter S180T (1.75 sq. ft.)
No accessories - no heater, water slide etc.
Hayward Aquarite 900 series SWG

I would like to replace the filter with a cartridge filter. If my pump should be replaced I'll do that as well.

Pump is 10' from one end of the pool, about 25' from the skimmer with underground 2" piping. There is one other 'inlet' on the pool's side (not a bottom drain type) about 6' closer to the pump than the skimmer. So, two inlets including the skimmer.
 
Jimrahbe said:
Your current pump will work just fine with a CCP-520

Why would you think it would not work?
Click to expand...
lol - Mostly because of analysis paralysis - too much research. I got hung up on looking at the the new variable speed pumps and tried to figure out how to use the pump size calculator here. I totally confused myself.

Thank you for your quick answer!!
 
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A,

With a large cartridge filter your filter pressure will probably be a lot less. This is not a bad thing as low filter pressure means there is not much restriction to the water flowing back to the pool.

At 1200 RPM, my filter pressure is about 1 or 2 lbs. I use a 30 lb. gauge so I can see it.

Thanks,

Jim R.
 
Jimrahbe said:
A,

With a large cartridge filter your filter pressure will probably be a lot less. This is not a bad thing as low filter pressure means there is not much restriction to the water flowing back to the pool.

At 1200 RPM, my filter pressure is about 1 or 2 lbs. I use a 30 lb. gauge so I can see it.

Thanks,

Jim R.
Click to expand...

Good to know. I have a 'normal' gauge on my sand filter and 'clean' is 15 or 16 lbs. Thanks for the heads up.

I ordered the filter today - delivery is scheduled for the 9th.
 
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A,

You should always have a 3-way valve between the pump and the filter so that you can shut off the filter if you want to open the pump lid, and it would allow you to vacuum to waste.

Thanks,

Jim R.
 
New filter arrived last Friday - installed everything on Sunday - so far so good! I started it up Monday at 6am and am doing a SLAM process.

Based on how my water looked and openings in past years it's clearing up very quickly. I can see my vacuum's hazy outline at the bottom of the deep end already!

Last week I also had a dozen trees removed that were throwing things in my pool - every evergreen (no more pine needles!) in sight as well as four oaks. I'm hoping for much cleaner openings in the future.
 
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My pool passed the OCLT test Friday night - pool looks great. Pool was crystal clear - until:

As I do every Sunday, I opened the strainer basket at the pump to check and clean it if necessary.

I turned off the pump and opened the strainer basket. I did not touch the new filter. As I inspected and hosed off the strainer basket I could hear gurgling noises. I basically ignored them as they were similar in sound to what I usually heard there when I did this maintenance when I had my sand filter attached.

I put the strainer basket back together, opened the valve at the top of the filter to let the air out, turned on the pump and the filter filled with water. I closed the valve at the top of the filter when water started to come out.

Then I looked into the pool - it's cloudy - as if the filter may have dumped dirty water into the pool. What did I do wrong? Should I have opened the valve on the filter before I opened the strainer basket to relieve the pressure?

EDIT: It's been about an hour and the water seems to be nearly clean again...
 

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