DE filter sizing

zz28zz

Active member
Mar 26, 2018
37
Austin, Tx
Currently have a 60 sq ft DE grid filter that needs replacement. Thinking up getting a 80 or 100 sq ft DE filter. Pump is a 2.5 hp single speed. With old filter, press was abt 26 psi just after replacing DE. Typically in abt 1 month, it would be up to 35 psi. The pressures always seemed high to me and always wondered if the prev owner install the right size filter to begin with.

Are filters sized by the pump or the pool size or both?
 

cowboycasey

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TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
A bigger filter will not change pressure but it may get you a longer time between cleaning.. so it will still start at 26 psi...

DE is great at filtering every little thing out of the water but you see the problem with that... You would also be way better served by grabbing a VS pump and running it at 800 to 1000 rpm and your pressure would be about 4 psi :)

If your pump made it through the freeze then you could drop a V Green VS motor on there and be good.. Just need to find out if you need a square or round flange..

600 to 700 for a great VS motor is worth every penny, I changed mine to a 1.65 V Green and love it... You will need the 2.7 HP and will fit your 2.5 HP pump perfect :)


grab a SALT or SCS seal and a rebuild kit when you do it..
 

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hwy17

Well-known member
Mar 17, 2021
175
Northern California
I'm not sure I could agree that a larger filter size won't decrease pressure. I think they are directly correlated.

A 2.5HP single speed certainly sounds oversized though, so I'm not sure a larger filter is a better solution than a smaller or VS pump.
 

ajw22

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Jul 21, 2013
29,166
Northern NJ
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Pentair Intellichlor IC-60
What model filter do you have? Your signature says Polaris DE filter. I didn't know Polaris makes filters.

If the pump actual GPM flow rate is greater then the maximum filter flow rate it can cause high pressures.

Post pics of your equipment pad and let us see what you got.
 

zz28zz

Active member
Mar 26, 2018
37
Austin, Tx
Filter is a Pentair Nautilus 60 sq ft DE type. (I fixed signature),
My understanding is that pressure is the result of flow VS restriction, so less restriction with same flow= less press (differential press across filter).

I'm assuming the fliter pump HP being high might have to do with the Spa's "massage performance" from the jets.

I think my pump survived (lid didn't) so I'll run it till it drops, then go the green route when it dies (won't have a choice).

Currently, water temp is rising. Bottom is dirty. I need to get filter online ASAP. Other projects like fixing heater and other optional upgrades will have to wait.
 

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ajw22

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Jul 21, 2013
29,166
Northern NJ
Pool Size
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Pentair Intellichlor IC-60
FNS 60 is the largest size FNS filter Pentair offers. Pentair specs say it is good to 120 gpm. You are not flowing at 120 gpm through your equipment pad.

For a larger DE filer you are going to the Quad D.E 80 or 100 filter that uses cartridges and DE. Quad DE 80 and 100 are speced at 160 gom.

It is up to you but a FNS 60 should be fine for your pool.

I see a separate spa jet pump on your pool pad.
 

zz28zz

Active member
Mar 26, 2018
37
Austin, Tx
Ok thx. I'm assuming that when I do upgrade to the 2.7 hp green pump, the FNS60 will still be OK?

The other 2.5 hp pump in the pic is for a water fall feature.
That's the pump I'm currently using to circulate water while awaiting parts. It was already winterized when storm hit.
 
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