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Buy a cartridge filter for clearer water and no wasted water; buy a sand filter for lower cost, faster cleaning and more tolerance of neglect. Cartridges filter down to roughly 10 to 20 microns, sand to about 20 to 40, so a cartridge visibly catches more. But a sand filter backwashes in two minutes, costs less to buy, and its media lasts five to seven years against two to five seasons for a cartridge. Both need servicing on pressure, not on the calendar.
Those are the two filters most residential pools actually choose between. Diatomaceous earth filters out-filter both — down to a few microns — but they carry more maintenance and are less common on new residential installs, so they sit outside this comparison.
Side by side
| Cartridge | Sand | |
|---|---|---|
| Particle size caught | About 10 to 20 microns | About 20 to 40 microns |
| Water clarity | Noticeably better | Good, occasionally hazy with fines |
| Cleaning method | Remove and hose; periodic chemical soak | Backwash through a multiport valve |
| Time to clean | 15 to 30 minutes | 2 to 3 minutes |
| Water used per clean | Almost none | 200 to 500 gallons |
| Media life | 2 to 5 seasons | 5 to 7 years |
| Media replacement cost | $40 to $150 per cartridge | $100 to $250 of sand |
| Unit purchase price | Higher | Lower |
| Flow resistance | Lower — easier on the pump | Higher |
| Waste setting for vacuuming | None | Yes, via multiport |
| Tolerance of neglect | Poor — pleats collapse if left dirty | Good |
The case for cartridge
Cartridge filters win on the two things people most often care about. The water is clearer, because the pleated fabric physically traps smaller particles than a sand bed does — and clarity is not merely cosmetic, since a pool you cannot see the bottom of is a genuine safety problem as well as an unpleasant one. And they waste essentially no water, because there is no backwash. In a region with drought restrictions or expensive municipal water, that alone can decide it.
They also present less resistance to flow, which means the pump works less hard for the same turnover. On a variable-speed pump running at a low filtration speed, lower resistance translates directly into lower electricity use, and the two upgrades complement each other.
The trade-off is the cleaning ritual. It is a proper job: shut the pump down, relieve the pressure at the air relief valve, open the housing, lift the element out, hose down every pleat from top to bottom, and reassemble with the O-ring cleaned and lubricated. Two or three times a season the cartridge also needs an overnight soak in a filter cleaner, because body oils, sunscreen and mineral scale build up inside the fabric where a hose cannot reach. Skip the soaks and the cartridge stops working long before it looks worn out.
The other honest drawback: cartridges are unforgiving. A sand filter left dirty for an extra month recovers with a backwash. A cartridge run heavily clogged loses pleat structure permanently, and once the pleats collapse against each other the element is finished regardless of how it looks.
The case for sand
Sand filters are the default on above-ground pools and a huge number of in-ground ones, for good reasons. They cost less to buy, the media is cheap and lasts five to seven years, and cleaning takes two minutes: turn the pump off, set the multiport to backwash, run for two minutes until the sight glass clears, rinse for thirty seconds, return to filter. There is nothing to disassemble and no O-ring to damage.
They are also forgiving. A sand bed keeps working reasonably well while dirty, and it recovers fully from a backwash, which suits a pool where maintenance is occasionally deferred. And the multiport valve brings the single most useful feature either filter offers — the waste position, which routes water straight out of the system bypassing the media entirely. That is what makes vacuuming dead algae practical, because the debris leaves rather than loading the filter.
One hard rule with a multiport: never move the handle while the pump is running. Doing so destroys the internal spider gasket, and a failed spider gasket produces a filter that silently returns unfiltered water to the pool.
The real weakness of sand is fine particles. Dead algae after a shock treatment, silt washed in by a storm, and the finest suspended matter all sit at or below what a sand bed reliably catches, which is why a pool can go hazy again shortly after vacuuming. A clarifier that clumps those particles into larger ones solves it, but it is an extra product and an extra step.
Service both on pressure, not the calendar
This is the single most useful maintenance habit for either type. When the media is new, write down the pressure the gauge shows with the pump running — that is your clean baseline. Once the gauge sits roughly 8 to 10 psi above that baseline, flow has dropped enough to matter and it is time to clean.
| Gauge reading | What it means | Action |
|---|---|---|
| At baseline | Filter clean, flow normal | Nothing |
| 8 to 10 psi above baseline | Media loaded | Backwash, or remove and hose the cartridge |
| Above baseline and stays there after cleaning | Media exhausted, or scale bound into it | Chemical soak, or replace the media |
| Below baseline with cloudy water | Water is bypassing the media | Check for channelled sand, a torn cartridge, a failed standpipe or a bad spider gasket |
| Falling steadily over days | Blockage before the filter | Check skimmer and pump baskets, and prime |
The fourth row is the one that catches people out. Low pressure feels like good news and is often the opposite — it means water is finding a path around the media rather than through it, and no amount of backwashing will fix it.
Size up, not down
Whichever type you pick, an oversized filter is a better pool and a cheaper one to run. A larger filter has more surface area, so it clogs more slowly, runs at lower resistance, needs cleaning less often, and lets the pump move water using less energy. Undersizing produces the opposite in every respect and is a common regret in owner reviews of budget above-ground setups.
Match the filter to the pool volume and the pump's flow rate, not to the smallest unit the pump will tolerate. If you are between two sizes, take the larger. And if you are also choosing a pump, do that alongside the filter — the pair have to suit each other, and the comparison is in variable-speed vs single-speed pool pump and what size pool pump do I need.
The verdict
Choose a cartridge filter if you want the clearest water, if water is expensive or restricted where you live, if you run a variable-speed pump and want the lowest flow resistance, or if the filter sits somewhere a backwash line would be awkward. Accept that you will spend twenty minutes on it every month or so and soak it a few times a season.
Choose a sand filter if you want the lowest purchase price and the least demanding routine, if the pool sees heavy debris loads, or if you want the waste setting for algae recovery and manual vacuuming. Accept that fine particles occasionally get through and that each backwash sends a few hundred gallons down the drain.
We do not buy or physically handle the equipment we rank — our verdicts come from aggregated owner ratings and expert consensus, described on how we rank.
Where to go next
If the water is cloudy right now, cloudy pool water works through all five causes including filtration failure. For the cleaning interval question specifically, how often to clean a pool filter cartridge. To pair the filter with the right pump, what size pool pump do I need and the best pool pumps. Everything else sits under the pools and spas hub.