How much stabilizer for a 5,000 gallon pool

In a 5,000 gallon pool, 6.7 oz (191 g) of stabilizer granules raises cyanuric acid (CYA) by 10 ppm. Taking fresh water from 0 to 40 ppm needs 1.7 lb (765 g). Liquid stabilizer is weaker by weight: 20 fl oz per 10 ppm.

Stabilizer doses for 5,000 gallons

5,000 US gallons (18,927 L).
Change	Granules (99%)	Liquid (25%)
Raise 10 ppm	6.7 oz	20 fl oz
Raise 20 ppm	13 oz	0.31 gal
Raise 30 ppm	1.3 lb	0.47 gal
Raise 40 ppm	1.7 lb	0.63 gal
Raise 50 ppm	2.1 lb	0.78 gal
CYA 40 → 70 (salt pool)	1.3 lb	0.47 gal

Run it with your numbers

Add

1.7lb

of Stabilizer granules (cyanuric acid 99%)

27 oz765 g

Raises CYA from 0 ppm to 40 ppm in 5,000 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.

Pool Calc for iPhoneComing soon to the App Store

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 5,000 gallon pool

That is about the size of a 15 ft round × 52 in above-ground pool (about 5,070 gal), or a 16 ft round × 48 in above-ground pool (about 5,260 gal). At 5,000 gallons, most doses are measured in fluid ounces or ounces rather than gallons or pounds. Above-ground pools of this size usually have vinyl liners, so keep calcium hardness modest and add everything in front of a return jet, away from the liner wall.

Questions

How much stabilizer for a 5,000 gallon pool?

6.7 oz of granular cyanuric acid per 10 ppm. From 0 to 40 ppm: 1.7 lb.

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.