Sand vs. Cartridge vs. DE: Which Pool Filter Should You Buy?
Pick by how much work you want to do, not by microns. A CARTRIDGE filter is the simplest — no multiport valve, no backwashing, rinse the element with a hose — and it's the right call for most small and mid-size pools. A SAND filter is the set-and-forget default: the media lasts 3–5 years (glass 5–7+), you backwash when the pressure climbs, and it shrugs off a heavy debris load. A DE filter gives the clearest water of the three, and it charges for it in labour — you recharge the powder after every single backwash, the grids need periodic deep-cleaning and eventually replacing, and the powder itself is a genuine respiratory hazard that needs careful handling. One thing to know before you compare: the 20–40 / 10–20 / 2–5 micron ladder quoted all over the internet is a dealer convention, not a manufacturer spec — we checked Hayward's own filter pages and their 28-page DE filter manual and neither publishes a micron rating at all. The spec the makers actually publish is filter AREA in square feet. So treat the microns as a rough ranking, not a measurement, and decide on labour, water use and running cost instead.
Every pool filter comparison online ranks these three the same way — sand is coarse, cartridge is finer, DE is finest — and settles it on microns. That ranking is right. The numbers underneath it are shakier than anyone lets on, and once you know that, the decision gets simpler rather than harder: you’re really choosing how much work you want to do.
The one-line answer
Cartridge if you want simple. Sand if you want hands-off. DE if you want the clearest water and you’ll do the work for it. All three will keep a properly-chlorinated pool clear — filtration polishes water that’s already balanced, it doesn’t rescue water that isn’t. So the honest tiebreaker isn’t fineness. It’s labour, water use, and what you’ll spend every season keeping the thing fed.
How each one actually works
A cartridge filter is a pleated element, like a large paper coffee filter folded into a cylinder. Water passes through the pleats and dirt stays behind. When it loads up you pull the element and rinse it with a hose. No multiport valve, no backwash line, fewer parts to fail.
A sand filter pushes water down through a bed of media — silica sand, or recycled glass — and dirt lodges in the gaps between the grains. When the bed fills, you backwash: reverse the flow and flush the trapped dirt out to waste. The media itself lasts years.
A DE filter is the different one. Inside are fabric-covered grids, and you coat them with diatomaceous earth — a fine powder of fossilised algae skeletons — poured in through the skimmer. Water passes through that powder coating, which is what makes it fine. Backwashing flushes the dirt and the powder out together, so every backwash ends with you mixing and adding a fresh charge.
The micron ladder, and the thing nobody tells you
Here’s the table everyone publishes, us included:
| Filter / media | Widely quoted as filtering to |
|---|---|
| Sand | 20–40 µm |
| Glass media (in a sand filter) | 10–15 µm |
| Cartridge | 10–20 µm |
| DE | 2–5 µm |
Now the part that isn’t on any rival page: those numbers are a dealer convention, not a manufacturer specification. We went looking for a maker to stand behind them, and came up empty:
- Hayward’s own pool-filter landing page mentions microns zero times.
- Hayward’s 28-page ProGrid D.E. Filter owner’s manual mentions microns zero times. Its spec table has a column headed “Effective Filtration Rate” — measured in square feet. That’s filter area, not particle size. The only descriptive claim in the entire manual is that the D.E. coating “filters out even the minutest particles,” which is marketing language with no number behind it.
Every single source we could find quoting the 2–5 / 10–20 / 20–40 ladder is a dealer or a reseller repeating it from another dealer. We’ve kept the table above because the ranking is real and useful — DE genuinely is the finest of the three, sand genuinely is the coarsest. But treat it as a rough ordering, not a measurement, and don’t pay a premium for a decimal place nobody will put their name to.
This is the same standard we hold everywhere on this site: when a maker publishes no number, we say so rather than borrowing a third party’s. It applies to filter media too — the recycled glass we recommend there publishes no micron rating either.
What the makers do publish is filter area in square feet, and that turns out to be the more useful spec anyway. More area means more surface catching dirt, which means longer between cleanings and less strain on your pump. When you’re comparing two filters of the same type, area is the number to read.
The three trade-offs that actually decide it
1. Labour — and this is the real decision. A cartridge asks for a hose rinse every couple of weeks. A sand filter asks for a backwash when the pressure climbs and a media change every 3–5 years. A DE filter asks for a backwash plus a fresh powder charge every single time, a grid deep-clean once or twice a season with the filter taken apart, and grid replacement eventually. Nothing about that is hard. There’s just steadily more of it, forever.
2. Water. Cartridge filters waste none — you rinse the element and lose essentially no pool water. Sand and DE both backwash, sending roughly 250–500 gallons to waste each time, often weekly in swim season. In Florida, or anywhere on restrictions, that’s the difference that matters most.
3. Fineness. DE is the finest, and on a pool that stays slightly hazy no matter what you do, it’s the type that fixes it. But most pools aren’t fighting a haze — and if yours is, the cause is usually chemistry rather than filtration. Buy DE because you want that last increment of polish and accept its upkeep, not because a filter will make up for water that’s under-chlorinated.
What owning a DE filter is actually like
This is the section the comparison pages skip, and it’s the one that should decide it for you.
You recharge after every backwash. The powder goes out with the dirt. So the routine isn’t “backwash and walk away” — it’s backwash, then measure out the right amount of DE, mix it into a bucket of water, and pour it slowly into the skimmer while the pump runs. Every time.
The grids need real maintenance. Once or twice a season you take the filter apart, pull the grid assembly and deep-clean it, because DE and oils build up in the fabric in ways backwashing won’t shift. Grids tear and eventually get replaced. It’s a bigger job than anything a cartridge or sand filter will ask of you.
And the powder is a genuine respiratory hazard. Not “it’s a bit dusty” — a real one, and the reason is worth understanding because it’s the part buyers get wrong.
Pool-grade DE is not garden-grade DE. Pool DE is flux-calcined, and calcining converts the harmless amorphous silica in raw diatomaceous earth into crystalline cristobalite. On the maker’s own safety data sheet — Dicalite’s, for flux-calcined diatomaceous earth — that classifies it under the OSHA hazard communication standard as Carcinogenic, Category 1A, with the signal word Danger, and IARC lists crystalline silica as Group 1, carcinogenic to humans. The sheet states that prolonged inhalation of dust containing respirable crystalline silica may cause lung disease, silicosis and lung cancer. Handle it with a proper respirator, don’t create airborne dust, and follow the label. This is entirely manageable — it just isn’t optional, and you’ll be doing it several times a season.
One more practical note: check your local rules on disposal. Spent DE and DE-laden backwash water are treated differently from place to place, and some jurisdictions restrict discharging them to a storm drain or septic system. We’re not going to tell you what your county says — check locally before you build a backwash routine around it.
The third option almost nobody publishes: DE in a sand filter
You don’t have to own a DE filter to get some of DE’s fineness. Adding a small amount of DE powder through the skimmer coats a sand bed and lets it trap much finer particles than sand alone. It’s the standard fix when a sand filter won’t clear a persistent haze, and we already recommend it in our cloudy water guide.
The honest catch: it washes out with every backwash, so you re-add it each time — which is DE’s labour problem in miniature. And overdoing it packs the bed, restricts flow and drives your pressure up. Start with a fraction of what a DE filter would take, and treat it as an occasional tool rather than a permanent conversion.
The same powder-handling caution applies. It’s the same product.
Does a screen enclosure change the answer?
It shifts it toward finer filtration, which is worth knowing if you’re in Florida.
A screen enclosure keeps out most leaves and heavy debris. What it doesn’t keep out is fine dust and pollen — the mesh is far too open for that. So a caged pool sees a lighter total load but a finer one, and fine particles are exactly what a coarse medium passes straight through and what shows up as a faint haze on a sunny afternoon.
An open pool under trees is the opposite case: a lot of bulk debris, where a sand filter’s willingness to swallow a heavy load matters more than the last few microns. So cage pushes toward cartridge, glass media, or DE; open and leafy pushes back toward sand.
Where the money actually goes
Sticker price is the least interesting number here, because all three are consumable-driven over a decade.
- Cartridge: the element is the consumable. Replace it every season or two — more often on a busy pool — and that’s most of your running cost.
- Sand: the cheapest to run by a distance. Media lasts 3–5 years (glass 5–7+), and a bag of sand is inexpensive. What you pay instead is water, every backwash.
- DE: powder every backwash, all season, every season, plus grids periodically. It’s the highest ongoing cost of the three, and the cost is in your time as much as your wallet.
That ordering doesn’t reverse. If lowest running cost is what you’re optimising for, a sand filter running glass media is very hard to beat.
So which one?
- Small or mid-size pool, want the least fuss → cartridge. Simplest hardware, no backwashing, no water wasted. This is the right answer for most above-ground pools and plenty of in-ground ones.
- Bigger pool, lots of debris, want to think about it as little as possible → sand. The media lasts years and it handles a heavy dirt load without complaint. Run glass media and you close most of the fineness gap too.
- You want the clearest water available and you’ll do the maintenance → DE. It genuinely is the finest of the three. Go in knowing about the recharge-every-backwash routine, the grid cleaning, and the powder handling.
- Undecided, and honestly? Most people should take one of the first two. DE’s advantage is real but narrow, and its upkeep is not. If you’re on the fence, the tiebreaker isn’t microns — it’s whether you’d genuinely enjoy the extra hour a month.
Don’t know your gallons? The pool volume calculator works it out from a few measurements. And whichever type you land on, size it by flow, not by horsepower — an oversized pump channels a sand bed and filters worse, which is the single most common way people make their water quality worse while trying to improve it. Our pump sizing calculator matches the pump to the filter.
Where to go next
- Above-ground pool? The decision narrows to two, and we’ve written it up specifically: sand vs. cartridge for an above-ground pool, with the crossover around 10,000–12,000 gallons.
- Going cartridge, in-ground: our best in-ground cartridge filters — the multi-element units, settled by size, and by the thing that actually decides your coverage: the model number. Hayward’s online SKU is the SHORT warranty; Pentair’s online SKU is the LONG one; Jandy gives you none at all.
- Going cartridge, above-ground: our best above-ground cartridge filter pumps, ranked by real filtered flow rather than the inflated GPH on the box.
- Going sand: our best above-ground sand filter systems, every pick verified as a complete pump-and-tank system.
- Already have a sand filter? The medium inside it is the cheapest upgrade available: sand vs. glass vs. filter balls.
- Buying an in-ground DE or cartridge filter? Read our warranty research first. Every major brand guts or voids the warranty on an online purchase — Jandy voids it outright — so for these, a dealer is usually the cheaper buy once something goes wrong.
- Filter not keeping up? Start with pump and filter troubleshooting before you replace anything.
FAQ
Frequently asked
Which pool filter is best: sand, cartridge, or DE?
There isn't one best — they trade fineness against labour. A cartridge is the simplest to live with and needs no backwashing, which makes it the easiest choice for most small and mid-size pools. A sand filter is the most hands-off day to day and its media lasts years, so it suits a bigger or dirtier pool. A DE filter produces the clearest water but asks the most of you: recharge the powder after every backwash, deep-clean and eventually replace the grids, and handle a powder that carries a genuine respiratory hazard. Pick the labour you're willing to do, because all three will keep a properly-chlorinated pool clear.
Does a DE filter really filter to 2 microns?
That figure is a widely-repeated industry range, not a manufacturer specification, and it's worth knowing the difference. We checked Hayward's own pool-filter pages and their 28-page ProGrid D.E. owner's manual: neither states a micron rating anywhere. The manual's 'Effective Filtration Rate' column is measured in square feet — that's filter AREA, not particle size — and the only descriptive claim in its prose is that the D.E. coating 'filters out even the minutest particles.' Every source we found quoting 2–5 microns is a dealer or reseller. DE genuinely is the finest of the three; the specific number just isn't something the makers publish.
Is DE powder dangerous?
Handled carelessly, yes, and this is the part most comparison pages skip. Pool-grade DE is flux-calcined, and calcining converts the harmless amorphous silica in raw diatomaceous earth into crystalline cristobalite. On the maker's own safety data sheet — Dicalite's, for flux-calcined DE — that puts it under the OSHA hazard standard as Carcinogenic Category 1A with the signal word 'Danger,' and IARC classifies crystalline silica as Group 1, carcinogenic to humans. The sheet states plainly that prolonged inhalation of dust containing respirable crystalline silica may cause lung disease, silicosis and lung cancer. This is not the same product as the food-grade DE sold for garden use. It's manageable — wear a proper respirator, don't create dust, follow the label — but it is a real hazard and you'll be handling it several times a season.
Can you put DE in a sand filter?
Yes, and it's a genuinely useful trick that almost nobody writes about. Adding a small amount of DE powder through the skimmer coats the sand bed and lets it trap much finer particles than sand alone — it's the standard fix for a haze a sand filter won't clear. The catch is that it washes out with every backwash, so you re-add it each time, and overdoing it clogs the bed and drives your pressure up. Think of it as a way to borrow some of DE's fineness when you need it, not as a permanent upgrade to a DE filter.
Does a screen enclosure change which filter I should get?
It shifts the argument toward finer filtration. A cage blocks most leaves and heavy debris, so your filter sees less bulk and proportionally more fine dust and pollen — which is exactly the load that a coarse medium passes straight through and that shows up as a faint haze. On an open pool dropping leaves all season, a sand filter's ability to swallow a heavy dirt load matters more. Under a cage, the fine stuff dominates, which argues for a cartridge, glass media in a sand filter, or DE.
Which filter wastes the least water?
A cartridge, by a wide margin — it doesn't backwash at all. You pull the element and rinse it with a garden hose, so you lose essentially no pool water. Sand and DE filters both clean themselves by backwashing, which sends roughly 250–500 gallons to waste each time, often weekly in season. In Florida and anywhere on water restrictions that's a real cost, and it's one of the few places where the three types differ by a lot rather than a little.
How often do you have to recharge a DE filter?
After every backwash, without exception — backwashing flushes the powder out along with the dirt, so the grids are left bare until you add a fresh charge through the skimmer. That's the single biggest lifestyle difference between owning a DE filter and owning the other two. On top of that the grids need a periodic deep clean (typically once or twice a season, taking the filter apart) and eventually replacing. None of it is difficult; there's just steadily more of it than a sand or cartridge filter asks for.