Micron Ratings: How Finely Does Each Filter Clean?
The primary performance metric for any pool filter is its micron rating. A single human hair is approximately 70 microns in diameter; the human eye cannot see individual particles smaller than 35 to 40 microns without magnification.
- Sand Filters (20 to 40 Microns): Water is pumped through a bed of #20 silica sand or crushed glass. While sand easily traps leaves, dead bugs, and coarse silt, fine dust and single-cell algae slip right through, resulting in slightly slower water polishing.
- Cartridge Filters (10 to 15 Microns): Water passes through pleated spunbound polyester fabric. Cartridges trap fine pollen, suntan lotions, and dead algae spores that sand filters miss.
- Diatomaceous Earth Filters (2 to 5 Microns): Grids are coated in microscopic fossilized diatoms. DE filters capture microscopic bacteria and fine silt on a single pass, delivering unmatched crystalline water clarity.
Operational Maintenance & Water Consumption
Filtration quality comes with trade-offs in weekly maintenance routines and water utility consumption:
Side-by-Side Comparison: Sand vs Cartridge vs DE
| Feature | Sand Filter | Cartridge Filter | DE Filter |
|---|---|---|---|
| Micron Rating | 20 to 40 microns | 10 to 15 microns | 2 to 5 microns |
| Water Clarity Polish | Good (crystal with clarifier) | Very Good (sharp clarity) | Exceptional (diamond shine) |
| Routine Cleaning | 5-minute valve backwash | 1-hour element hose down | Backwash + recharge with powder |
| Water Loss per Clean | 150 to 300 gallons | Zero gallons to waste | 150 to 300 gallons |
| Media Lifespan | 5 to 7 years (sand) | 3 to 5 years (cartridges) | Grids last 5 to 8 years |
| Internal Pressure Drop | Moderate (8 to 15 PSI) | Lowest (low head loss) | Highest (spikes fast when dirty) |
How to Choose the Best Filter for Your Setup
- Choose Sand if: You prioritize minimal labor, have plenty of cheap water for backwashing, and want durable equipment that only needs attention once every 5 years.
- Choose Cartridge if: You live in water-restricted regions, use a variable speed pump, or hate dealing with multiport valves and chemical backwash lines.
- Choose DE if: You demand commercial-grade clarity, host large pool parties, and do not mind handling diatomaceous earth powder and disassembling grids once a year.
cartridge vs sand vs de pool filter FAQs
Can I convert my sand filter to glass media?
Yes. Crushed recycled glass media drops into any standard sand filter and improves filtration down to 5 to 9 microns while reducing backwash water consumption by 25 percent.
Is diatomaceous earth dangerous to handle?
DE powder used in pool filters is dangerous if inhaled dry because crystalline silica damages lung tissue. Always wear a dust mask when scooping dry DE powder and mix it with water in a bucket before pouring into the skimmer.
Why is my cartridge filter pressure always high?
High starting pressure indicates that polyester pleats are clogged with hardened calcium scale or body oils. Clean the cartridge in an automated degreaser bath followed by a diluted acid soak.
Can you backwash a cartridge filter?
No. Cartridge filters do not have multiport valves or backwash lines. Cleaning requires shutting off the pump, opening the tank, and spraying pleats with a pressurized hose nozzle.
More pool guides
- How to Clean a Pool Filter: Complete Sand, Cartridge, and DE Guide
Master step-by-step cleaning procedures for cartridge, sand, and diatomaceous earth filters.
- How to Change Sand in a Pool Filter: Step-by-Step Guide
Safely change sand filter media, protect fragile laterals, and restore sparkling clarity.
- How to Size a Pool Pump: GPM, Horsepower, and Head Loss Guide
Calculate exact flow rates and head resistance to select the ideal pump horsepower.