How much stabilizer for a 1,000 gallon pool

In a 1,000 gallon pool, 1.3 oz (38 g) of stabilizer granules raises cyanuric acid (CYA) by 10 ppm. Taking fresh water from 0 to 40 ppm needs 5.4 oz (153 g). Liquid stabilizer is weaker by weight: 4 fl oz per 10 ppm.

Stabilizer doses for 1,000 gallons

1,000 US gallons (3,785 L).
ChangeGranules (99%)Liquid (25%)
Raise 10 ppm1.3 oz4 fl oz
Raise 20 ppm2.7 oz8 fl oz
Raise 30 ppm4 oz12 fl oz
Raise 40 ppm5.4 oz16 fl oz
Raise 50 ppm6.7 oz20 fl oz
CYA 40 → 70 (salt pool)4 oz12 fl oz

Run it with your numbers

gal

Not sure? Work out your pool volume.

ppm
ppm

30 to 50 for manual chlorine; 60 to 80 with a salt cell.

%

Add

5.4oz

of Stabilizer granules (cyanuric acid 99%)

153 gabout ¾ cup by volume

Raises CYA from 0 ppm to 40 ppm in 1,000 gal.

  • This is a large change. Add it in stages and retest between them.
  • Also raises cyanuric acid (stabilizer). It only comes down by replacing water.
  • Put the granules in a sock in the skimmer basket or in front of a return. Do not backwash for a week.
  • Stabilizer takes several days to dissolve and register on a test. Do not add more in the meantime.
  • At CYA 40 your free chlorine minimum becomes 3 ppm and the target 6 ppm.
  • Adding too much is hard to undo: only draining lowers CYA. If unsure, add three quarters, wait a week and retest.

Check the product label. Strengths vary by brand, so enter the % printed on yours. Add one chemical at a time, into the water, and never mix chemicals.

Save this test and get reminded when it is time to retest.

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About stabilizer

Granules dissolve slowly. Put them in a sock or the skimmer basket with the pump running, and don’t backwash for a week. CYA takes several days to show fully on a test, so don’t top it up before then.

Overshooting is the expensive mistake: nothing you can add lowers CYA, only replacing water does. If you are unsure of your volume, add three quarters of the dose, wait a week and retest.

Manual chlorine pools usually run CYA 30 to 50. Salt water pools run 60 to 80, because the cell makes chlorine all day. Your chlorine target rises with CYA: see the FC/CYA calculator.

Dosing a 1,000 gallon pool

A 1,000 gallon pool is usually a large inflatable, a stock tank or a small frame pool. Doses this small are easy to overshoot: one extra splash is several ppm. Measure stabilizer with kitchen measures you keep only for pool chemicals, and test after every addition.

Small pools also lose chlorine fast on sunny days because there is so little water. Test daily, and when the numbers drift far off it is often quicker to drain and refill than to correct them.

Questions

How much stabilizer for a 1,000 gallon pool?

1.3 oz of granular cyanuric acid per 10 ppm. From 0 to 40 ppm: 5.4 oz.

How long does stabilizer take to dissolve?

Granules can take several days to a week to dissolve and register on a test. Wait a week before adding more.

How do I lower stabilizer if I add too much?

Only by replacing water. The drain and refill calculator shows how much.