What is the difference between a sand and cartridge pool filter?
The difference is what traps the dirt and how you clean it out. A sand filter fills a tank with a bed of special filter sand (or glass media), and as pool water flows down through it the sand grains catch debris. A cartridge filter uses a pleated polyester element, like a giant version of an engine air filter, and the folds strain particles out as water passes through. Both then return clean water to the pool.
The practical split comes down to cleaning. A sand filter is cleaned by backwashing: you flip a valve to reverse the water flow, which lifts the trapped dirt off the sand bed and flushes it out the waste line. A cartridge filter has no backwash valve at all. When it clogs, you shut the pump off, lift out the cartridge, and hose it clean, then drop it back in. That single design choice drives almost every other tradeoff between the two.
Sand is the coarsest of the three common filter types and cartridge sits in the middle, with DE (diatomaceous earth) filtering the finest. Our best pool filter guide walks through all three if you are still deciding on a type rather than a specific unit.
Which one filters the water cleaner?
The cartridge filters cleaner. A cartridge traps particles down to roughly 10 to 20 microns, while sand only catches down to about 20 to 40 microns, so a cartridge pulls out finer haze and dust that sand lets slip through. In side-by-side use, cartridge-filtered water often looks a touch crisper, especially in a pool that sees a lot of fine dust, pollen, or sunscreen.
Sand can close some of that gap. Swapping the sand for glass filter media filters finer and lasts longer, and adding a small scoop of DE powder or cellulose fiber to a sand filter temporarily sharpens it down toward cartridge territory. Those are real fixes, but they are extra steps a cartridge does not need. Our best filter sand and media guide covers which media buys the biggest clarity jump.
If your water is cloudy, know that the filter type is only half the story. A hazy pool is usually a chemistry or circulation problem, not a filter that is too coarse. Balance the water first, run the pump long enough for a full turnover, and use our cloudy pool guide before you blame the filter.
Which is cheaper and easier to maintain?
Sand is cheaper to own and lower-effort day to day, but it wastes water. The sand itself is cheap and only needs replacing every 5 to 7 years, and a backwash takes about two minutes: flip the valve, run it until the sight glass clears, flip it back. The catch is that each backwash sends 200 to 500 gallons of pool water down the drain, and you refill and rebalance that water afterward. In a drought or on metered water, that adds up.
A cartridge wastes no water, but you do more of the work by hand and buy new elements sooner. Cleaning means pulling the cartridge and hosing the pleats, then soaking it in filter cleaner a couple times a season to cut out sunscreen and oils. Cartridges wear out in about 2 to 5 years and cost $40 to $150 or more each to replace, and large systems may use a set of four. Our how to clean a pool filter guide covers doing both jobs right so the media lasts.
Both share one rule: clean when the pressure gauge climbs about 8 to 10 psi above the clean reading, not on a calendar. A bigger filter of either type stretches every cleaning interval, runs at lower pressure, and lets your pump work less, so oversizing the tank is one of the better upgrades you can make.
Sand or cartridge: which should you buy for your pool?
Pick a cartridge for most residential in-ground pools. It filters finer, skips backwashing so it wastes no water, runs at lower pressure to save pump energy, and has no multiport valve to leak or fail. It is also the friendlier choice for a saltwater pool and for anywhere with water restrictions, which is why cartridge is the type most new pools ship with.
Pick sand if you have a large pool, a heavy debris load from nearby trees, or you simply want the most hands-off routine. Sand shrugs off big dirt without clogging as fast, a backwash is quicker than rinsing pleats, and the cheap, long-lived media keeps running costs down. Owners who would rather flip a valve than wrestle a wet cartridge are happier with sand.
Whichever type you choose, size it to your pump and pool, not to gallons alone. The filter has to handle your pump's flow rate, so start from your pool volume and turnover with the pool volume calculator and the pump size calculator, then buy a filter rated comfortably above that flow. See our best pool filter picks for specific units.
Sand wins on
- +Lowest hands-on effort: a two-minute backwash beats rinsing pleats.
- +Cheap media that lasts 5 to 7 years before replacement.
- +Handles large pools and heavy debris without clogging fast.
Cartridge wins on
- +Filters finer (about 10 to 20 microns) for clearer water.
- +Wastes no water; great for saltwater pools and water restrictions.
- +No multiport valve to fail and lower pressure, saving pump energy.
The verdict
Buy the cartridge filter for a typical residential in-ground pool. It filters cleaner, wastes no water, runs at lower pressure to save pump energy, and plays nicely with saltwater, which is why most new pools come with one. Choose sand instead if you run a large pool, live under a lot of trees, or want the most hands-off routine, because sand handles heavy debris and cleans in a two-minute backwash with cheap, long-lasting media. Size whichever you pick to your pump flow using the pump size calculator, and compare specific units in our best pool filter guide.
Related: Best pool filters, Best filter sand and media, How to clean a pool filter.
Frequently asked questions
What are the disadvantages of a sand filter?
Sand is the coarsest of the three common filter types, catching particles only down to about 20 to 40 microns, so very fine haze can slip through. Backwashing also wastes 200 to 500 gallons of water each time you clean it, and the sand itself rounds off and channels after about 5 to 7 years and has to be replaced. Swapping in glass media filters finer and lasts longer if that clarity matters to you. See our how to clean a pool filter guide for doing it right.
Do you backwash a cartridge filter?
No. A cartridge filter has no backwash valve. To clean it you shut off the pump, remove the cartridge, and hose the pleats off, then soak it in filter cleaner a couple of times a season to cut sunscreen and oils. That is the main reason a cartridge wastes no water while a sand filter loses a few hundred gallons per backwash.
What type of pool filter is most effective?
DE (diatomaceous earth) filters the finest at roughly 2 to 5 microns, then cartridge at about 10 to 20 microns, then sand at about 20 to 40 microns. DE gives the clearest water but takes the most maintenance. For most residential pools, a cartridge is the best balance of clarity and effort. Our best pool filter guide compares all three.
What size sand filter do I need for a 10,000 gallon pool?
Size the filter to your pump's flow, not to gallons alone. A 10,000 gallon pool that turns the water over in 8 hours needs a pump moving roughly 20 gallons per minute, which pairs with about a 19 to 22 inch sand tank (around 1.4 to 1.9 square feet of filter area). Confirm the numbers with the pool volume calculator and the pump size calculator, then buy a filter rated comfortably above your pump's flow.
What is the best filter for an above-ground pool?
For most above-ground pools, a cartridge filter is the easy pick: there is no backwash plumbing to run, it is cheap to operate, and you just hose the element off. Larger above-ground pools with a heavy debris load do fine with a small sand filter, which handles big dirt without clogging as fast. Match either to your pump flow, and see our best pool filter picks.