How much stabilizer to add to a pool
The formula
Example: 20,000-gallon pool, current CYA 10 ppm, target 40 ppm. Increase needed = 30 ppm.
(30 × 20,000) ÷ 7,500 = 80 oz (5 lbs)
Always base the dose on your current CYA reading, not an assumption. If you haven’t tested CYA recently, test it first — adding stabilizer to a pool that already has 40 ppm would push it to 70+ ppm, which creates a different problem. See high CYA in a pool for why that matters.
Dose chart by pool size
Ozs of granular stabilizer to raise CYA by target amount
| Pool size | +10 ppm | +20 ppm | +30 ppm | +40 ppm |
|---|---|---|---|---|
| 10,000 gal | 13 oz | 27 oz (1.7 lb) | 40 oz (2.5 lb) | 53 oz (3.3 lb) |
| 15,000 gal | 20 oz (1.25 lb) | 40 oz (2.5 lb) | 60 oz (3.75 lb) | 80 oz (5 lb) |
| 20,000 gal | 27 oz (1.7 lb) | 53 oz (3.3 lb) | 80 oz (5 lb) | 107 oz (6.7 lb) |
| 25,000 gal | 33 oz (2.1 lb) | 67 oz (4.2 lb) | 100 oz (6.25 lb) | 133 oz (8.3 lb) |
| 30,000 gal | 40 oz (2.5 lb) | 80 oz (5 lb) | 120 oz (7.5 lb) | 160 oz (10 lb) |
Don’t know your pool volume? Use the pool volume calculator to find it by shape and dimensions before dosing.
How to add stabilizer correctly
- Measure the dose. Calculate using the formula above based on your current CYA reading and target. For most pools starting from zero or near-zero, one 4–5 lb bag is the right order of magnitude.
- Pre-dissolve in warm water. Fill a clean 5-gallon bucket about two-thirds full with warm tap water. Slowly pour in the granular stabilizer and stir. It dissolves slowly — give it 5–10 minutes and stir periodically. The solution will be cloudy; that’s normal.
- Pour near a return jet. With the pump running, slowly pour the dissolved solution directly into the pool near a return jet. This distributes it into the circulation. Don’t dump it in one spot.
- Run the pump continuously. Keep the pump running for at least 24 hours to circulate and distribute the CYA through the entire pool volume.
- Wait 24–48 hours before retesting. CYA takes time to fully dissolve and distribute. A retest at 24 hours often reads lower than the final value because granules are still dissolving. If the 24-hour reading seems low, test again at 48 hours before adding more.
Never add stabilizer to the skimmer basket
Some guides suggest adding granular stabilizer to the skimmer and letting pool water dissolve it. This is risky: undissolved granules can clog the basket, the skimmer neck, or the pump basket, and creates a high-concentration slug of CYA that doesn’t distribute evenly. Always pre-dissolve in a bucket first.
What product to buy
Pool stabilizer, pool conditioner, and cyanuric acid are all the same chemical — granular cyanuric acid (CYA). The name on the bag doesn’t matter. Buy the largest bag that fits your dose calculation; the per-ounce cost drops significantly in bulk. A 4 lb bag runs about $10–15 at pool supply stores and big-box retailers in season.
Dichlor granules and trichlor tablets also add CYA as a byproduct of chlorination — but these are chlorine products, not stabilizer products. If you’re adding CYA intentionally, use pure granular cyanuric acid so you control exactly how much you’re adding. See which chlorine products add CYA for a full breakdown.
How often do you need to add stabilizer?
If you’re using liquid chlorine (sodium hypochlorite) as your primary sanitizer: add stabilizer once at the start of the season to reach 30–50 ppm, then test CYA monthly. CYA drifts downward slowly from dilution — splash-out, backwashing, and rain — typically 5–10 ppm over a full summer. A small top-up of 13–26 oz per 10,000 gallons mid-season is common.
If you’re using trichlor tablets as your primary sanitizer: you probably don’t need to add stabilizer at all. Trichlor adds significant CYA with every dose — the bigger risk is CYA climbing too high over the season, not too low. Test CYA monthly and watch for it creeping toward 70–80 ppm. See high CYA in a pool if it does.
Fresh fill or major drain: start from scratch
After a full drain and refill, or opening a new pool, CYA starts at zero. Use the dose chart above based on your pool volume and target (30–50 ppm for a regular pool, 60–80 ppm for a saltwater generator pool). Don’t rely on any residual CYA — test first, then dose.
Get the exact dose for your pool
Enter your pool size, current CYA, and target and the calculator does the math — ounces, pounds, and how many bags to buy.
CYA Dilution Calculator →Or track it over time in the app:
Frequently asked questions
How much pool stabilizer do I add?
oz to add = (target CYA increase × pool gallons) ÷ 7,500. For a 15,000-gallon pool going from CYA 10 to 40 ppm (+30 ppm), that’s 60 oz (3.75 lbs). Use the dose chart above for common pool sizes.
How long does pool stabilizer take to work?
24–48 hours to fully dissolve and distribute. Run the pump continuously during this period. Don’t retest and add more at 12 hours — wait a full 48 hours for the most accurate reading before deciding if a top-up is needed.
Can you add too much stabilizer?
Yes, and it’s a real risk because CYA can only be removed by draining. If CYA is already at 30–50 ppm, don’t add more. If you accidentally overdose, a partial drain is the only fix. Calculate based on your current CYA and target, not a rule of thumb.
Where do you add stabilizer in a pool?
Pre-dissolve in a bucket of warm water, then pour slowly near a return jet with the pump running. Never add to the skimmer basket — it can clog and doesn’t distribute evenly.
How often do you add stabilizer?
For liquid chlorine pools: once at season start to reach 30–50 ppm, then a small top-up mid-season if CYA drifts below 30 ppm. For trichlor tablet pools: usually never — tablets add CYA continuously and the risk is accumulation, not depletion.
CYA / Pool Stabilizer Series
- Pool Stabilizer (CYA) — what it is, ideal levels, and how to manage it (start here)
- Best CYA Level for Liquid Chlorine Pools
- How to Lower CYA in a Pool
- How to Raise CYA in a Pool
- High CYA in a Pool — Causes, Symptoms, and Fixes
- Low CYA in a Pool — Risks and How to Fix It
- How Much Stabilizer to Add to a Pool
- Best CYA Level for Saltwater Pools
Keep reading
- How to Raise CYA in a Pool — full step-by-step process beyond just the dose
- What Is CYA (Pool Stabilizer)? — how it works, ideal levels, and target ranges by pool type
- High CYA in a Pool — what happens if you add too much and how to fix it
- Low CYA in a Pool — signs that CYA is too low and how UV is burning through your chlorine
- CYA Dilution Calculator — calculates gallons to drain if CYA is too high
- Pool Volume Calculator — find your pool’s gallons if you’re not sure
- Does Liquid Chlorine Raise CYA? — which chlorine products add CYA and which don’t