Concept understanding on filter sizes

Flboy44

Well-known member
Jan 30, 2022
137
Central Florida
Pool Size
12000
Surface
Fiberglass
Something that I am trying to wrap my head around, and I know I am missing something! When it comes to a filter, sizing, DE versus cartridge. A cartridge filter at 100 ft.² is woefully inadequate for almost any situation, in my opinion. But when looking at DE filters, they are measured in terms of 40 ft.² being a large filter. What am I missing? I am in the school of, bigger is better, when it comes to filters.
 
You are comparing 2 different types of mediums. The DE filter uses grids plus the coating of DE which becomes the true filter medium. The cartridges filter relies only on the grid.
DE filters can be backwashed regularly to remove the captured dirt and replace the DE.
Cartridge filters need to be disassembled to clean grids. The recommendation for a larger cartridge filter is to allow it more area to capture dirt between cleanings. a 100 sq ft cartridge will become clogged quicker than a 300 sq ft cartridge.
 
44,

As a reference, I have a Pentair CCP 520 on my 17K pool...

I was originally cleaning it every six month, just on a schedule, as my pressure barely moves as the filter gets dirty. I have now changed to cleaning it once a year before the pool season starts.. The pool itself is never closed for the Winter.

I should also note that I use hairnets in my skimmers...

Thanks,

Jim R.
 
Filter Sizing:

  • High rate sand filtration: Size for 15 gallons per minute (gpm) per square foot of filtration surface area.
  • DE: Allow 1 gpm per square foot of surface area.
  • Cartridge: Limit flow to 0.375 gpm per square foot of surface area.
 
Take the top, middle and bottom range of all 3 filter styles and they will have comparable cleaning intervals

Small : 100lb sand / 20 sq ft DE / 100 sw ft cart

Medium : 200lb sand / 40 sq ft DE / 300 sq ft cart

Large : 300lb sand / 60 sq ft DE / 500 sq ft cart

With an open yard or a cage, medium is probably plenty. Heavy debris / wooded areas need large filters.
 
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