The same pool needs wildly different filter sizes depending on the media — because filters are sized by flow rate, not pool volume directly. Enter your volume to see the square footage for sand, cartridge, and D.E., and check whether your pump is too strong for the filter.
A filter is sized by the flow it must handle, not by a square-foot-per-gallon rule. Your pool volume sets the flow you need to turn the water over in your target time, and then each media type filters at a different rate per square foot: sand handles the most flow per square foot, D.E. far less, and cartridge the least — which is why a cartridge filter for the same pool needs many times the surface area of a sand filter. Filter area = required flow ÷ the media's rated flow per square foot. The recommended sizes here use typical design rates; the minimums use the NSF Standard 50 maximum rates, which are the smallest legal sizes.
With filters, oversizing is good: a larger filter runs at lower pressure, traps finer debris, and goes longer between cleanings, so it's common to size up 50–100% beyond the minimum. The dangerous mistake is the opposite — a pump that pushes more flow than the filter is rated for. Too much flow channels through sand, blows out cartridges, and filters poorly. Enter your pump's flow above to check it against the filter's maximum. The sand-charge weight is a rough figure (~150 lb per 10,000 gallons); the exact sand or D.E. powder amount depends on your specific filter model's tank or grids, so always check its manual.
A 24,000-gallon pool, 8-hour turnover, needs ≈ 50 GPM. At design rates that's about 3.3 sq ft of sand, 25 sq ft of D.E., or 133 sq ft of cartridge — same pool, very different sizes by media.