How much chlorine for a 40,000 gallon pool

To raise chlorine by 1 ppm in a 40,000 gallon pool, use about 8.2 oz of 65% cal-hypo shock, 9.5 oz of 56% stabilized chlorine (dichlor) or 41 fl oz of 12.5% liquid chlorine. Keep free chlorine between 1 and 3 ppm.

Chlorine: amount to raise free chlorine

Product	+1 ppm	+2 ppm	+3 ppm	Shock (+10 ppm)
Shock / granular (cal-hypo) 65%	8.2 oz	1.03 lb	1.54 lb	5.14 lb
Stabilized granules (dichlor) 56%	9.5 oz	1.19 lb	1.79 lb	5.96 lb
Liquid chlorine 12.5%	41 fl oz	82 fl oz	123 fl oz	3.2 gal
Household bleach (regular, unscented) 8.25%	62 fl oz	124 fl oz	1.45 gal	4.85 gal

Other products

Goal	Product	Amount
Raise alkalinity by 10 ppm	Alkalinity increaser (baking soda)	6.01 lb
Raise stabilizer (CYA) by 10 ppm	Stabilizer (cyanuric acid)	3.34 lb
Salt from 0 to 3,200 ppm (salt water pool)	Pool salt (no iodine)	1,068 lb
Weekly maintenance in a floater	3-inch chlorine tablets	6 to 7 tablets a week

Calculate with your readings

The calculator below already has this pool's volume. Enter what your test showed to get the right dose of each product.

1How big is the pool?

Inflatable or kiddie poolAbove-ground or in-ground poolI know how many gallons

Capacity it's on the box or the pool's label

RectangularRoundOval

Length (ft)

Width (ft)

Diameter (ft)

Average depth (ft) the water depth; if there's a shallow and a deep end, use the average

Gallons

Does the pool have a filter (pump)?

No filtermost inflatable poolsHas a filterpump plugged in

2What does the water look like?

Clear and sparklingjust maintainI've just filled itfresh waterCloudy or milkydull waterGreen or slimyneeds a shock

3Which chlorine do you have?

Pool shock / granular chlorinecal-hypo, the most common powderStabilized chlorine granulessays "stabilized" or "dichlor" on the packageLiquid pool chlorineHousehold bleachregular, unscented, not splash-lessChlorine tabletsgo in a floater or chlorinator and dissolve slowly

I have a test kit (optional)

Chlorine (ppm)

Result

Estimate. Check the product label (if it differs, follow the label), add one product at a time and test again before anyone swims.

How to add it

Test free chlorine, pH and alkalinity with a test kit.
Fix alkalinity first, then pH, and chlorine last.
Dissolve granular chlorine in a bucket of pool water and pour it around the pool with the pump running.
Wait 4 to 6 hours with the pump running and test again before swimming.

Safety

Never mix different products, dry or dissolved. Add one at a time, with a gap in between.
Dissolve granules in a bucket of pool water before adding them. Always add the product to water, never water to the product.
Wear gloves and eye protection when handling acid and chlorine. Store away from children and out of the sun.
These are estimates for home use. Always follow the manufacturer's label and test again after dosing.

In case of an accident: call 911 or Poison Control at 1-800-222-1222, and have the product container with you.

Frequently asked questions

How many ounces of chlorine for a 40,000 gallon pool?

To raise it by 1 ppm, about 8.2 oz of 65% cal-hypo shock. For daily maintenance, usually 1 to 2 ppm.

How many chlorine tablets for a 40,000 gallon pool?

As a starting point, 6 to 7 tablets a week (8 oz), always in a floater or chlorinator, never directly in the pool. The amount varies by brand: check the label. Tablets only maintain chlorine; for green or cloudy water, use shock or liquid chlorine.

How much liquid chlorine for a 40,000 gallon pool?

About 41 fl oz of 12.5% liquid chlorine for each 1 ppm.

What about household bleach?

With regular 8.25% bleach, about 62 fl oz for each 1 ppm. Use only regular unscented bleach (not splash-less) and check the % on the label: weaker bleach needs more.