Filter Comparison Chart

The best type of filter depends on the usage of the pool as well as the preferences of the pool owner/operator and the local city codes.  The chart below will help you to determine the best filter for your situation.

Filter Type Sand DE Cartridge FilterMedia Sand Diatomaceous Earth Paper Filters Filtration Efficiency Good 40 microns Best 5 microns Good 10 microns Cleaning Method Internal Backwash Internal Backwash Disassemble and Clean with Hose Backwash Line or Hose Required Yes Yes No Frequency Of Cleaning When loaded Every 4-8 Weeks Varies Widely, depending on unit Recommended Application Home Pools Apartment Pools Home Pools NOT for Apt. Pools Home Pools NOT for Apt. Pools Water Clarifier Needed? Sometimes Never Sometimes How Often Media Replaced? 6 years (home use) 3 years (apt. use) Each Backwash 2-4 years Cost to Replace Filter Media $50 - $100 for sand (excludes labor) $2.00 - $4.00 for DE $200 - $300 for a new set of grids  (excludes labor) Varies, but can be VERY expensive Annual Maintenance None Required DE Filter Clean $75.00 Cartridge Cleaning periodically. Positive Points Easy to maintain Filter Media cheap Infrequent Repairs Best filtration Simple to maintain Easy to repair Negatives Poorest Filtration "Wastes" water in  weekly backwash Backwash a bit complicated Repairs not cheap Not allowed in every municipality. Cartridges can be a bit costly, check cost before buying filter. Filter cleaning not as easy as others

Filter Sizing

Once you have chosen the right type of filter for your pool, it is important to get it sized properly.  It must be sized to match the pump which in turn must match the circulation needs of the pool.  If the filter is undersized, it will fill up quickly and also can be damaged by the force of the pump.  If the filter is undersized, it may not backwash well.

Recommended flow rates for different sizes of SAND FILTERS Tank Diameter 19" 21" 24" 30" 36" Surface Area 1.8 sq. ft. 2.3 sq. ft. 3.1 sq. ft. 4.9 sq. ft. 6.9 sq. ft. Max Flow Rate 40 GPM 50 GPM 60 GPM 100 GPM 140 GPM Recommended flow rates for different sizes of D.E. FILTERS Surface Area 24 sq. ft. 36 sq. ft. 48 sq. ft. 60 sq. ft. 72 sq. ft. Max Flow Rate 48 GPM 72 GPM 96 GPM 120 GPM 144 GPM Best Flow Rate 36 GPM 54 GPM 72 GPM 90 GPM 108 GPM Manufacturers will specify the Max flow rate. I recommend staying with the Best flow rate to avoid crushing grids due to high pressure. Recommended flow rates for different sizes of CARTRIDGE FILTERS Surface Area 100 sq. ft. 200 sq. ft. 300 sq. ft. 400 sq. ft. 500 sq. ft. Max Flow Rate 38 GPM 75 GPM 112 GPM 150 GPM 150 GPM Best Flow Rate 30 GPM 50 GPM 75 GPM 100 GPM 125 GPM Manufacturers will specify the Max flow rate. I recommend choosing the Best flow rate for best filtration and better dirt loading capacity.

Note that these recommendations are only approximations based on typical conditions.   On-site analysis must be done to insure that the filter matches up properly with the pump and the pool.  If the plumbing runs on the equipment are particularly long, then the resistance to flow in the piping will be greater and intake lines may need to be larger than specified in this chart. You must account for pipe sizes number of skimmers Note also that this may differ from the recommendations listed by the manufacturer .  It is usually better to oversize the filter.  Water flows through the filter media at a slower velocity Finer filtration Longer filter cycles.