Flow rate for Cartridge Filter

[jimmieg]

I want to switch from my DE Filter to a Cartridge Filter.

My in ground pool/ spa combination is approximately 15,000 gals.

I have a Jandy JEP 2.0 VS pump that has a max output of 152gpm at 3450rpm's as best I can determine from charts.

The size of my pool and the normal speed of filtering would easily fit the specs of the Waterway 325. But it's max flow rate is 120gpm.

Only time I crank the pump to highest setting is when we use the spa.

Would I be safer going with the oversized Waterway 425 at 150 gpm flow rate, or am I missing something about spa usage flow rate?

Thanks!

 

[proavia]

The larger the filter area the less you have to clean the filter.
If the price difference is within your budget, get the larger filter.
425 square feet of cartridge area isn't really oversized for your 15k gallon pool. We recommend buying the largest filter you can, based on your budget.

While your present pump may be rated at 152gpm at 3450rpm,, it's likely not able to produce that number as it doesn't include efficiency losses do to your plumbing setup.

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[Jimrahbe]

Jim,

I agree with Gene... The bigger the filter the less you have to clean it..

What marketing says the pump will do is more counting on the perfect world.. What the pump will do, happens in the real world.

I would not worry about the GPM numbers.

If your current DE filter works, then a large cartridge filter will just work better...

Thanks,

Jim R.

 

[JamesW]

The pump flow rate depends on the system curve.

It is unlikely that you would exceed 100 GPM.

The maximum recommended flow for a cartridge is 0.375 GPM/sqft.

At 325 sqft, that is 122 gpm maximum.

The 325 should be fine.

I would prefer a 420 to 520 sqft model, but the 325 will work.

https://cdn.fluidrausa.com/-/media/zodiac/global/downloads/jandy/pumps/h0490000.pdf

https://cdn.fluidrausa.com/-/media/zodiac/global/downloads/jandy/pumps/54409_sl.pdf

 

[JamesW]

The red line is a typical System Curve.

The blue line would give you 120 GPM, but that is not a typical system curve.

Basically, there is pretty much zero chance of exceeding 120 GPM.

y=0.00382(x)^2, x from 0 to 150 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

 

[Newdude]

Graph of only needing to clean my 500 sq ft filter once a season.

 

[Newdude]

On a serious note, filters last a generation. Divide the upcharge over 20+ years and it's peanuts if it saves 1 cleaning a year, and an absolute no brainer if it saves multiple cleanings a year.

 

[jimmieg]

Thanks! This is all helpful and charts are very interesting!

I was confused as my daughter recently built a pool in FL approx same size as mine, and builder used a single cartridge Jandy (only 200 Sq ft) and it seems to serve them well after 1+ year.

But, we have more growing stuff near our pool, Santa Ana winds, etc. I will say both my robotic skimmer/robotic cleaner added this year takes a big load off filter and netting 3x/day when windy here. My wife thanks me daily.

For ~ $200 difference I will probably go with larger cartridge filter as I really have no place to backwash current DE filter anymore and full cleaning is a mess.

And I have updated my signature with equipment. Let's see if I got it right.

 

[ajw22]

And I have updated my signature with equipment. Let's see if I got it right.

Not yet.

Signature area is different then your Profile.

Create your signature

 

[jimmieg]

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Created signature, but don't see it in this response. Something else to check or turn on?

 

[jimmieg]

Created signature, but don't see it in this response. Something else to check or turn on?

Ahh...seeing it in landscape. Thanks!

 

[1poolman1]

Thanks! This is all helpful and charts are very interesting!

I was confused as my daughter recently built a pool in FL approx same size as mine, and builder used a single cartridge Jandy (only 200 Sq ft) and it seems to serve them well after 1+ year.

But, we have more growing stuff near our pool, Santa Ana winds, etc. I will say both my robotic skimmer/robotic cleaner added this year takes a big load off filter and netting 3x/day when windy here. My wife thanks me daily.

For ~ $200 difference I will probably go with larger cartridge filter as I really have no place to backwash current DE filter anymore and full cleaning is a mess.

And I have updated my signature with equipment. Let's see if I got it right.

Florida is the capital of undersized filters.

 

[jimmieg]

Florida is the capital of undersized filters.

Is there a particular reason they use smaller filters in FL?

 

[Newdude]

None officially. I can think of 2 possibilities.

1) so many are caged, or wide open without much need for a bigger filter

2) with so many pools and service companies, it's an unspoken rule there to let them charge for frequent cleanings.

 

[ajw22]

Is there a particular reason they use smaller filters in FL?

Many pools in FL are inside of cages and do not get lots of dirt and debris blown into them.

Unfortunately Pool Builders install their standard packages on all their builds and outdoor pools end up with small filters.