Three filter types dominate residential pools: sand, cartridge, and DE. Each has a clear profile of strengths and weaknesses. There's no universal “best” — but there is a clear best for most Florida homeowners.
Sand filters
How it works: Water flows through a bed of #20 silica sand. Particles catch in the sand grains. Backwashing reverses flow to flush debris out the waste line.
- Filtration: 20–40 microns nominal (weakest of the three)
- Maintenance: Easiest — backwash a couple minutes when pressure is high
- Water use: ~300 gallons per backwash — meaningful in drought seasons
- Sand replacement: Every 5–7 years
- Cost (installed): $800–1,500
Cartridge filters
How it works: Water flows through pleated cartridge elements. Particles catch on the pleats. Cleaning means pulling the cartridge and hosing it off.
- Filtration: ~10–15 microns
- Maintenance: Hose off every 2–4 months, chemical soak every 6 months
- Water use: Zero (no backwashing)
- Cartridge replacement: Every 2–3 years
- Cost (installed): $1,000–2,000
DE (diatomaceous earth) filters
How it works: Water flows through fabric-covered grids dusted with DE powder. DE powder catches microscopic particles.
- Filtration: ~3 microns (finest)
- Maintenance: Backwash and recharge DE when pressure is high; full strip and clean annually
- Water use: Backwash water + used DE
- Grid replacement: Every 5–10 years
- Cost (installed): $1,500–3,000
Side-by-side
| Metric | Sand | Cartridge | DE |
|---|---|---|---|
| Clarity | Good | Better | Best |
| Ease | Best | Good | Worst |
| Water use | High | None | Medium |
| Initial cost | $ | $$ | $$$ |
| Lifetime cost | $$ | $$ | $$$ |
Our recommendation for Florida residential
Oversized cartridge filter. Zero water waste matters during drought restrictions, filtration quality beats sand, and maintenance is hands-off compared to DE. Oversize by 50% above pump flow rate to extend service intervals to 4–6 months.
Want a pro to handle this?
Our CPO-certified techs run this exact playbook on every weekly service visit.