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How Much Salt Does Your Pool Need?

Reviewed 2026-04

Start with a fresh salt test. Use your pool gallons and generator limits to estimate a first addition by weight, then see how many bags to buy. Retest before adding more.

See how the calculations work in our methodology

Example volumes (gallons):

Need to estimate pool gallons? Use the Volume Calculator →

Use a fresh reading from an independent salt test kit

Model range: 2700–3400 ppm. Read the manual. For CircuPool SJ models, the manual gives an ideal range of 4,000–4,500 ppm; this preset targets 4,000 ppm.

Confirm your inputs

Before you use a dose, compare every input with your fresh tests and measured pool volume. Confirm each example value only after you’ve checked it. When you change a value, you’ll need to confirm it again.

Compare pool salt brands

Enter your measured gallons and fresh tests above to work out how much you need.

Affiliate disclosure: We may earn a commission when you buy through links on this page. Our recommendations are independent and this costs you nothing extra. Learn more›

Product option

Morton

Pool Salt · 40 lb bag

Check price on Amazon →

Salt weights and bags for shopping

Use these full-correction weights to plan a purchase; the 40 lb bag counts round up. For your first addition, use the calculator with a fresh salt test and your generator limits. Never pour in the table’s full amount at once.

Pool SizeTo Raise 500 ppmTo Raise 1,000 ppmTo Raise 2,000 ppmTo Reach 3,200 ppm (from 0)
5,000 gal21 lb (1 bag)42 lb (2 bags)83 lb (3 bags)133 lb (4 bags)
10,000 gal42 lb (2 bags)83 lb (3 bags)167 lb (5 bags)267 lb (7 bags)
15,000 gal63 lb (2 bags)125 lb (4 bags)250 lb (7 bags)400 lb (11 bags)
20,000 gal83 lb (3 bags)167 lb (5 bags)334 lb (9 bags)534 lb (14 bags)
25,000 gal104 lb (3 bags)209 lb (6 bags)417 lb (11 bags)667 lb (17 bags)

Salt weight (lb) = ppm increase × pool gallons × 8.34 lb/gal ÷ 1,000,000. Divide by 40 lb per bag and round up for shopping. Measure each staged addition by weight.

Affiliate disclosure: We may earn a commission when you buy through links on this page. Our recommendations are independent and this costs you nothing extra. Learn more›

Buying salt? Morton Pool & Spa Salt comes in a 40 lb bag. Measure your first addition by weight; a bag count is for shopping.

Check price on Amazon →

Frequently asked questions

Which salt target matches my generator?

Choose the preset only if it matches your exact model. Hayward AquaRite 900 AQR925/AQR940 uses a 3,200 ppm target within a 2,700–3,400 ppm operating range. CircuPool SJ15/SJ20/SJ40/SJ55 uses a 4,000 ppm target within 3,500–5,000 ppm. For another model, enter custom limits from its manual.

Should I add all the estimated salt at once?

Weigh out the first addition shown, which is 60% of the estimated correction. Use the whole-bag count for shopping. Wait at least 48 hours, or longer if your manual requires, then test salt independently and calculate the next addition. An uncertain pool volume or test can lead to too much salt, so never add the original remainder automatically.

Do I need to drain if salt is above my target?

First compare a fresh salt test with your model’s operating range. Being above your target can still leave you within that range. If you need water exchange, have a qualified professional assess construction, liner support and groundwater and plan it before lowering the water.

When can I switch the cell on after adding salt?

Keep the cell off until all the salt has dissolved and an independent test puts it within your model’s range. Use the generator and finish builder’s startup instructions. New or resurfaced plaster may need time to cure: the CircuPool SJ manual requires at least 30 days, or longer if the builder specifies. Use the conversion instructions for an existing pool.

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How we calculate this
Your result uses the formulas explained in our methodology. Read the assumptions for your calculation before you use the result.