Sand, cartridge, or DE — I've pulled apart and cleaned all three on South Florida routes for years, and there's no universal “best,” just a best for your pool. The whole decision comes down to three numbers: how fine each one filters, how much labor it demands, and what it costs to own.
The three filter types at a glance
Three filter types dominate residential pools: sand, cartridge, and DE. Here's the honest side-by-side before we get into each type.
| Metric | Sand | Cartridge | DE |
|---|---|---|---|
| Filters down to | 20–30 microns | ~10–15 microns | ~3 microns |
| Water clarity | Good | Better | Best |
| Ease of ownership | Best | Good | Worst |
| Routine maintenance | Backwash when pressure climbs | Hose off every 2–4 months | Backwash + recharge DE powder |
| Water use | ~300 gallons per backwash | Zero | Backwash water + spent DE |
| Media replacement | Sand every 5–10 years | Cartridges every 2–3 years | Grids every 5–10 years |
| Cost (installed) | $400–1,000 | $1,000–2,000 | $1,500–3,000 |
| Lifetime cost | $$ | $$ | $$$ |
For scale on those micron numbers: a human hair runs about 70 microns. Our filter micron chart maps what each rating actually catches. And on lifetime cost, sand and cartridge land about even once you count media replacements — DE stays the most expensive to own.
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. Easiest filter to live with — when the pressure gauge climbs 8–10 psi over its clean baseline, you backwash for a couple of minutes and you're done.
- Filtration: 20–30 microns nominal (weakest of the three)
- Water use: ~300 gallons per backwash — meaningful in drought seasons
- Sand replacement: Every 5–10 years
- Cost (installed): $400–1,000
The catch is what sand doesn't catch. At 20–30 microns, fine silt and dead algae sail straight through and back into the pool — which is why a sand-filtered pool can test clean and still look dull. Old sand also channels: water carves paths through the bed and stops filtering, and short backwash cycles are the tell.
Sand filter types: valve position and media
“Sand filter” isn't one product. They split two ways — where the valve sits and what's in the tank:
- Top-mount multiport:the valve sits on top of the tank. Compact and cheaper, standard on smaller pools — but the whole valve has to come off to change the sand.
- Side-mount multiport: the valve hangs on the side of the tank. Costs a little more, but sand changes go through the top dome without touching the plumbing. What I want on a bigger in-ground system.
- Media choices: #20 silica sand is the standard. Crushed-glass media catches finer debris and resists channeling; zeolite filters finer and grabs some ammonia compounds. Both cost more per bag than silica.
Full breakdown of where sand still makes sense — and the alternative-media specs — in our sand filter pros and cons for Florida deep dive.
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 — no backwash line, no water sent to waste.
- 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, $50–$200 per cartridge
- Cost (installed): $1,000–2,000
Do the hose-off right and the element lasts its full life; skip it and body oils blind the pleats early. Step-by-step in our pool filter cleaning guide.
DE (diatomaceous earth) filters
How it works:Water flows through fabric-covered grids dusted with DE powder. The powder catches microscopic particles down to about 3 microns — the finest filtration of the three, and the closest thing to polished water.
- 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
The trade is labor. Every backwash means recharging with fresh powder, and once a year the whole filter comes apart for a grid-by-grid cleaning. If DE powder ever shows up on your pool floor, a grid is torn — that's a repair, not a cleaning.
What South Florida does to your filter
Down here the filter never gets an off-season. It runs 12 months a year, so every media lifespan sits at the fast end of its range. Three local realities change the math:
- Summer storm season: afternoon storms load pools with leaf litter, palm fronds, and wind-blown organic debris from June through September, and the warm water feeds algae. Filters clog faster, and an undersized cartridge turns into a monthly chore.
- Spring pollen surge:February through May, pine pollen and oak catkins blanket the water and load every filter fast — sand backwash frequency doubles, and cartridge and DE pull ahead on the fine yellow dust.
- Dry-season water restrictions:backwash a sand filter every other week at roughly 300 gallons a shot and you're sending about 7,800 gallons a year down the waste line. A cartridge sends zero.
- Match the pump:a filter has a maximum flow rate, and an oversized pump can push water through sand so fast it stops filtering well. Size the filter to the pump — see our variable-speed pool pump guide for the flow math.
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 and the cleaning interval stretches from the standard 2–4 months to every 4–6 months instead of a monthly fight. Budgeting the whole equipment pad? Run your numbers through our pool service cost calculator first.
When to call a pro
Some filter problems are cleanings; some are repairs. Sand blowing back into the pool means a cracked lateral inside the tank. DE powder on the pool floor means a torn grid. A pressure gauge that won't come back down after a proper cleaning means the media is at the end of its life — or the problem is downstream of the filter entirely. And a brand-new cartridge that clogs within weeks means the filter was undersized on day one.
We diagnose and replace all three filter types across South Florida. If your filter is short-cycling, leaking at the tank seam, or just past its service life, book a visit through our pool repair serviceand we'll size the replacement to your pump — not the other way around.
Watch: What A DE Filter Actually Is | Sand vs Cartridge vs DE
Doug compares sand, cartridge, and DE filtration and explains the role of DE powder and grids in trapping fine particles.
Frequently asked questions
For most South Florida residential pools, an oversized cartridge filter. It filters to roughly 10–15 microns (finer than sand), uses zero backwash water during dry-season restrictions, and takes far less labor than DE. Oversize it about 50% above your pump's flow rate and the standard 2–4 month cleaning stretches to every 4–6 months.
Sand filters split by valve position and media. Top-mount multiport valves sit on the tank and cost less, but the valve has to come off for sand changes; side-mount valves make sand changes easier on larger in-ground systems. Media options are standard #20 silica sand, crushed glass that catches finer debris and resists channeling, or zeolite, which filters finer and grabs some ammonia compounds. Our sand filter pros and cons guide covers the media specs in depth.
Backwash when the pressure gauge reads about 8–10 psi over its clean baseline, not on a fixed calendar. Each backwash sends roughly 300 gallons down the waste line, so backwashing more often than the gauge demands just wastes water. If cycles get short, the sand is channeling or at the end of its 5–10 year life.
Roughly $400–1,000 for a sand filter, $1,000–2,000 for a cartridge filter, and $1,500–3,000 for a DE filter, installed. Ongoing media costs: replacement cartridges run $50–$200 each every 2–3 years, sand gets replaced every 5–10 years, and DE grids every 5–10 years.
About 2–3 years if you maintain them: hose the elements off every 2–4 months and give them a chemical soak every 6 months. Skip the cleanings and oils blind the pleats early. A brand-new cartridge that clogs within weeks usually means the filter is undersized for the pump.
Sand filters catch particles down to 20–30 microns, cartridge filters roughly 10–15 microns, and DE filters about 3 microns — the finest of the three. For scale, a human hair is about 70 microns, which is why a sand-filtered pool can test clean and still look dull.
No. Cartridge filters have no backwash line at all — cleaning means pulling the pleated elements and hosing them off. That zero-water-waste design is a real advantage in South Florida's dry season, when backwashing a sand filter every other week sends about 7,800 gallons a year down the waste line.
A torn grid. DE filters hold powder on fabric-covered grids, and when one tears, powder passes straight through the returns into the pool. That's a repair, not a cleaning — the filter needs to come apart and the damaged grid replaced before recharging with fresh DE.
Want a pro to handle this?
Our CPO-certified techs run this exact playbook on every weekly service visit.