Quick verdict
The finest filtration you can buy for a home pool. Worth it if crystal-clear water justifies the extra maintenance; skip it if you want low fuss.
Ideal for
- Owners who want the clearest possible water
- In-ground pools with fine-dust/pollen issues
- Enthusiasts who don’t mind hands-on maintenance
Not ideal for
- Low-maintenance seekers
- Well/drought areas (backwashing + D.E. disposal)
The full picture
If your priority is the clearest water money can buy, D.E. is the answer, and the Hayward ProGrid DE4820 is the mainstream 48-square-foot choice. Diatomaceous earth coats the internal grids and filters down to roughly 3–5 microns — finer than any sand or cartridge filter — leaving water noticeably crisper. The tradeoff is maintenance: you recharge D.E. powder after backwashing, and periodic teardown cleaning of the grids is part of ownership. The glass-reinforced copolymer tank and up-flow design are built for high capacity and durability. It's the enthusiast's filter — best water, most involvement.
Hayward ProGrid DE4820 D.E. Filter (48 sq ft) at a glance
- Filter type
- D.E.
- Filter area
- 48 sq ft
- Flow rate (GPM)
- 120
- Filtration (microns)
- 3–5
- Backwashing required
- Yes
- Filter media
- Diatomaceous earth (on grids)
- Tank material
- Glass-reinforced copolymer
- Valve
- Backwash valve (separate)
- Pool type
- In-ground
- Notable feature
- Filters to 3–5 microns — the clearest water of any type
Source: Compiled from manufacturer specifications, retailer listings, and aggregated owner feedback. Specs and prices change — confirm with the retailer before buying.
This is a research-based review — our analysis draws on manufacturer specifications, manuals, warranty terms, and verified owner feedback rather than our own hands-on testing, and we note where a detail couldn't be confirmed. How we review
The in-depth review
If your priority is the clearest possible water, D.E. is the answer, and the Hayward ProGrid DE4820 is the mainstream 48-square-foot choice.
Why D.E. water is clearer
Diatomaceous earth coats the internal grids with a microscopic filtering layer that traps particles down to roughly 3–5 microns — finer than sand (20–40) or cartridge (10–15). The difference is visible: D.E. pools often look noticeably crisper, and fine pollen and dust that slip through other filters get caught. The glass-reinforced copolymer tank and up-flow design deliver high capacity and durability to match.
The honest caveats
D.E. is the most hands-on filter type. After every backwash you recharge fresh D.E. powder through the skimmer, and a few times a year you open the filter to clean the grids. You also handle D.E. powder (wear a mask) and follow local rules on backwash and D.E. disposal. This is the enthusiast's filter — best water, most involvement.
Performance breakdown
Research-based editorial judgments from specs, warranty terms, and verified owner feedback — not lab measurements. How we score
Pros and cons
What works
- Finest filtration (3–5 micron)
- Noticeably crisper water
- Durable glass-reinforced tank
- High capacity, up-flow design
What doesn't
- Most maintenance of any filter type
- Recharge D.E. powder after backwashing
- Periodic grid teardown cleaning
- D.E. handling/disposal considerations
Best alternatives to Hayward ProGrid DE4820 D.E. Filter (48 sq ft)
Pentair
CC150 (160317)
Pentair
Pentair Clean & Clear CC150 Cartridge Filter (150 sq ft)
Best mid-size cartridge
The right-sized cartridge filter for typical pools — 150 sq ft of fine filtration and no backwashing, at a friendlier price than the giant multi-cartridge units.
Pentair
FNS Plus 48 (180008)
Pentair
Pentair FNS Plus 48 D.E. Filter (48 sq ft)
Premium D.E.
A premium D.E. filter with a tough fiberglass-reinforced tank and a single-nut grid pack — the clearest water with slightly easier servicing.
Hayward
Hayward Pro Series S244T Sand Filter (24 in)
Best value sand filter
The classic, low-fuss sand filter — cheap to run, forgiving, and dead simple, with a multiport valve that backwashes at the turn of a handle.
Hayward
Hayward SwimClear C3030 Cartridge Filter (325 sq ft)
Best overall
The set-and-forget cartridge filter — a huge 325 sq ft of media means fine filtration, long cycles between cleanings, and zero backwashing.
Frequently asked questions
Why is D.E. water clearer?
Diatomaceous earth coats the grids with a microscopic filtering layer that traps particles down to roughly 3–5 microns — finer than sand (20–40) or cartridge (10–15). That’s why D.E. pools often look noticeably crisper.
How much more maintenance is a D.E. filter?
More than sand or cartridge: after backwashing you must add fresh D.E. powder through the skimmer, and a few times a year you open the filter to clean the grids. It’s the price of the clearest water.
Is D.E. powder safe to handle?
Use pool-grade D.E. and avoid breathing the dust (wear a mask when adding it). Follow local rules on backwash and D.E. disposal, since some areas restrict discharging it to storm drains.
What size pool does the DE4820 handle?
Its 48 sq ft and high flow rating suit most residential in-ground pools. As always, ensure the filter’s flow rating exceeds your pump’s max flow.
How long do the grids last?
Often 5–10 years with proper care. Cleaning them gently and not running the filter at excessive pressure extends grid life; torn grids let D.E. back into the pool and should be replaced.
D.E. or cartridge for me?
D.E. gives clearer water but more maintenance and water use; cartridge is nearly as clear, simpler, and wastes no backwash water. If low fuss matters, choose cartridge; if ultimate clarity does, choose D.E.