How much salt for a 35,000 gallon pool

Starting with plain water, you'll pour roughly 934 lb of salt into a 35,000 gallon pool to hit 3,200 ppm (parts per million, the number a salt test shows). That works out to 24 bags at 40 lb each. Got some salt in the water already? Enter your reading and watch the bag count shrink.

Units Gallons, pounds Liters, kilograms

Pool volume in gallonsgal

Don't know the gallons? Measure the pool

Pool shapeRectangleOvalRoundKidney

A: lengthftB: widthftShallow end depthftDeep end depthft

The gallons above fill in as you measure.

Salt reading now ppmYour chlorinatorTarget to dose to ppm

Example For 35,000 gallons, from 0 to 3,200 ppm. Type yours to see your bags.

Buy 24 bags of

Add 934 lb in all: pour 23 bags now, then 14 lb from bag 24 after you retest.

Pump on. Pour it around the deep end, not into the skimmer.
Brush any salt off the floor until it's gone.
Run the pump 24 hours and test. Add the rest only if the reading is still short.

How this is worked out

Gallons = A × B × average depth × 7.5 for a rectangle, 6.7 for an oval and 5.9 for a round pool (diameter × diameter), the factors in Hayward's manual; 7.0 for a kidney (length × average width), from Inyo's sizing guide. Pounds of salt = (target ppm − your ppm) × gallons × 8.34 ÷ 1,000,000. A gallon of water weighs 8.34 pounds. Bags round up. In liters: kilograms = ppm difference × liters ÷ 1,000,000.

Salt for 35,000 gallons by current reading

Reading now	to 3,000 ppm	to 3,200 ppm	to 3,600 ppm
0 ppm	Buy 22 bagsadd 876 lb	Buy 24 bagsadd 934 lb	Buy 27 bagsadd 1,051 lb
1,000 ppm	Buy 15 bagsadd 584 lb	Buy 17 bagsadd 642 lb	Buy 19 bagsadd 759 lb
1,500 ppm	Buy 11 bagsadd 438 lb	Buy 13 bagsadd 496 lb	Buy 16 bagsadd 613 lb
2,000 ppm	Buy 8 bagsadd 292 lb	Buy 9 bagsadd 350 lb	Buy 12 bagsadd 467 lb
2,500 ppm	Buy 4 bagsadd 146 lb	Buy 6 bagsadd 204 lb	Buy 8 bagsadd 320 lb
2,800 ppm	Buy 2 bagsadd 58 lb	Buy 3 bagsadd 117 lb	Buy 6 bagsadd 234 lb
3,000 ppm	Already there	Buy 2 bagsadd 58 lb	Buy 5 bagsadd 175 lb

Every bag is 40 lb and the count rounds up. Pour all but the final bag, let the pump run a day, then test before you open it.

Intex and TruClear aim for 3,000 ppm, Hayward for 3,200 ppm and Pentair for 3,600 ppm. The chart by chlorinator lists every manufacturer's number.

Good to know at 35,000 gallons

In a pool this size, every 100 ppm gap takes 29.2 lb to close. So when your test reads 400 ppm under target, that's 117 lb: buy 3 bags of 40 lb.

CircuPool's advice is to buy a cell sized for 1.5 to 2 times the water you hold. For this pool that is 52,500 to 70,000 gallons, which fits the Pentair IntelliChlor IC60 or the Pentair IntelliChlor Plus60.

Questions people bring to the counter

How much does a backwash or a rainy week cost me in salt?

Only the water you lose takes salt with it. If a top-up brings this pool from 2,800 back to 3,200 ppm, that's 117 lb: buy 3 bags of 40 lb.

How can I tell if my pool has enough salt?

Test the water. Most chlorinators light a low-salt warning below their range. A strip or drop kit reads in ppm, and that number goes in the salt reading box.

Next size down or up: 30,000 gal or 40,000 gal. Every size is on the per 1,000 gallons chart.