Square Footage of Filters

tnt69

Active member
May 27, 2016
25
Chester, IL
I am researching AG Pool filters and would like to know how the measurement of Square Feet in the filter relates? I have a 21' X 43" x 54" oval AG Pool, around 30K gallons. The Cartridge system we have in the 9 year old pool is leaking terribly and getting worse so time to replace. The present filter I believe is a 100 square foot but I am not sure, and I clean it every other week or so. I see filters from 50 to 325+ square feet and would like to know how they differ and what is best for my pool. I replaced my pump last year so only need the filter. My pump is a 2HP 2Speed Waterway Millennium Hi-Flo.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,885
San Dimas, CA (LA County)
Bigger is better.

The only caveat is filters that need backwashing --- you need enough pump to get the flow to blast it clean.

That is not an issue with a cartridge filter, as it doesn't get cleaned by backwashing. You could hook a tiny garden-pond pump up to a gigantic cartridge filter that holds as much as the pond and it would work.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
31,287
Laughlin, NV
The minimum SF is 100 per 10000 gallons. Go much higher if you can. This reduces the cleaning effort dramatically. You should only be cleaning your filters once or twice a season.
For a 30K pool, a 400+SF cartridge filter is recommended.
 

markayash

Gold Supporter
Mar 21, 2016
2,149
Marietta Ga
I have a 28k pool and my cartridge filter is 425 sq ft. I clean it a few times a year but really only needs cleaning after spring pollen season in Ga. I just like to see what it’s catching. Only down side is it’s 4 cartridges so takes a little more time.
I agree Go as big as you can afford and have room for :)
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
18,347
Bedford, TX
tnt,

Just curious... Do you clean the filter twice a month because you need to, or because someone told you that is what you should be doing??

Do you run most of the time on low or high speed?

Thanks,

Jim R.
 
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Newdude

Well-known member
Jun 16, 2019
3,827
NY
Your pool is ginormous for an above ground. Go as big as you can afford. For reference I only have 5k more gallons than you and a 500 sq ft cartridge. It will cut your cleanings down to once or twice a season. I have a lot of oak trees so I clean mine after the pollen is done and mid season but I could probably skip the mid season cleaning.

the only thing I would change when I build another pool is I will go with the 4 cartridge filter instead of the 2. The square footage is the same but they are much lighter to take out and carry. It’s not a big problem for me now but all it takes is one slipped disc and it would be.
 
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markayash

Gold Supporter
Mar 21, 2016
2,149
Marietta Ga
Your pool is ginormous for an above ground. Go as big as you can afford. For reference I only have 5k more gallons than you and a 500 sq ft cartridge. It will cut your cleanings down to once or twice a season. I have a lot of oak trees so I clean mine after the pollen is done and mid season but I could probably skip the mid season cleaning.

the only thing I would change when I build another pool is I will go with the 4 cartridge filter instead of the 2. The square footage is the same but they are much lighter to take out and carry. It’s not a big problem for me now but all it takes is one slipped disc and it would be.
Wow, I looked up your filter, that cartridge is huge.
 

Newdude

Well-known member
Jun 16, 2019
3,827
NY
I have a 320 and love it, been going 5 years and no issues... Clean once a year at 1 or 2 PSI rise starts at 15 psi and goes to 17 in 10 months (y)
OP had double your gallons with 30k. So a 640 sq ft would be the equivalent for them and they don’t make them that big. 500/520 is the way to go IMHO.
 

Newdude

Well-known member
Jun 16, 2019
3,827
NY
Wow, I looked up your filter, that cartridge is huge.
It has a rough division of 2/3 to 1/3 between the 2 cartridges. The fat boy is about 300 sq ft and the Abe Lincoln hat tall one is 200. 4 X 130 would be a lot easier to move around. Especially when wet.
 

tnt69

Active member
May 27, 2016
25
Chester, IL
Jimrahbe,
I actually clean it that often because it needs it. The single 100 sq ft cartridge is plenty dirty and my psi will have went from 15 after a clean to 19. I have very few trees around although spring pollen is ridiculous. I run the pump on Hi most of the time and use to run it on Hi and 24/7. It will start up at 15psi on Hi and 4psi on low. A couple years ago I started putting a timer on it but that's when I noticed it would start leaking after it was shut down for a while. I obviously am way under sized on my filter, so hopefully getting a new one closer to the right size, I can go back to a timer again.
 

tnt69

Active member
May 27, 2016
25
Chester, IL
Thank you all for your input! I will definitely go with much bigger sq footage. Not sure we can swing the $$ of the big 4 cartridge models but will at least go 3 times bigger. In scouting out various filters, one of my biggest problems is the fact that I have a fairly new pump (in 2nd season) and finding the right filter that will either fit my base (not likely) or a system with the base but without a pump! Which brings up one more question...My 2hp pump moves the water in my pool fine now but especially with a large 4 cartridge setup or even a 2 cartridge, will that still be sufficient?
 
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Newdude

Well-known member
Jun 16, 2019
3,827
NY
The bigger the filter the more flow it allows. Think of it as breathing through a straw. Breathing through a thicker straw is easier.
 
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cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
3,593
Fletcher, OK

tnt69

Active member
May 27, 2016
25
Chester, IL
Is there any reason why a Cartridge Filter advertised for In Ground Pools could not be used for my AG Pool? It seems as though all or most of the bigger filters are all considered "In Ground".
 

Newdude

Well-known member
Jun 16, 2019
3,827
NY
None whatsoever. Your 30k gallons need way more filtering than a 12k gallon inground. Typical ‘above ground filters’ tend to be undersized. Go big or go home. :)
 
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