Pool Stabilizer Calculator
Calculate the exact amount of cyanuric acid (pool stabilizer / conditioner) needed to reach your target CYA level — for granular, liquid, dichlor, and trichlor sources.
Cyanuric acid does not evaporate or degrade. If you overshoot, the only fix is a partial drain and refill. Add in stages — dose for half the target increase, retest after 24 h of circulation, then add the rest.
- Cyanuric acid does not degrade significantly. Over-stabilization requires partial drain & refill.
- Add in stages: dose for half the target increase, retest after 24 h of circulation, then add the rest.
- Do not backwash for 48 h after adding granular CYA through the skimmer.
- Test CYA monthly during swim season with a drop-based kit (Taylor K-2006 / TF-100). Test strips are unreliable.
Cyanuric acid dosage quick-reference chart
Use this table to estimate the dose for a 10 ppm CYA increase across common pool sizes. The calculator above uses the exact same formula — multiply the table value by (target − current) ÷ 10 for your real increase.
| Pool volume | CYA 100% (lbs) | Stabilizer 56% (lbs) | Liquid 30% (gal) |
|---|---|---|---|
| 5,000 gal | 0.4 | 0.7 | 0.15 |
| 10,000 gal | 0.8 | 1.5 | 0.29 |
| 15,000 gal | 1.3 | 2.2 | 0.44 |
| 20,000 gal | 1.7 | 3 | 0.59 |
| 25,000 gal | 2.1 | 3.7 | 0.73 |
| 30,000 gal | 2.5 | 4.5 | 0.88 |
Values = dosage to raise CYA by 10 ppm. Multiply by (target − current) ÷ 10 for your actual increase.
What is the right CYA level for my pool?
Standard chlorine pool: aim for 30-50 ppm. Below 30 ppm, UV destroys your chlorine too quickly. Saltwater (SWCG) pool: aim for 60-80 ppm because the salt cell generates chlorine constantly and benefits from extra UV protection. Maximum useful: 100 ppm — beyond that, chlorine becomes sluggish and algae gets harder to kill.
Which stabilizer product should you choose?
100% cyanuric acid granular
The cleanest dose per pound — every gram you add is CYA. Best when you need a precise, large increase and want to keep shipping weight low.
56% stabilizer granular
The most common retail form (e.g. HTH, Guardex). Same active ingredient, just diluted with filler. Dose scales up proportionally.
Liquid stabilizer (~30% CYA)
Acts almost instantly — no skimmer or waiting period. It is heavy and expensive per ppm, but it is the right pick when you need CYA today and cannot wait for granular to dissolve.
Dichlor (56% CYA)
Convenient chlorine + stabilizer in one puck. Every 1 ppm FC raises CYA by ~0.9 ppm — fine for occasional use, risky as the primary sanitizer on a SWCG pool.
Trichlor (90% CYA)
Slow-dissolving tabs or sticks. Highest CYA contribution of any common sanitizer — easy to over-stabilize a pool within a single swim season.
How to add stabilizer
- Test your current CYA with a drop-count kit (Taylor K-2006 or TF-100).
- Decide your target. 30-50 ppm for standard pools, 60-80 ppm for saltwater.
- Add half the calculated dose via the skimmer with the pump running.
- Circulate for 24 hours, then retest CYA before adding the second half.
- Do not backwash the filter for at least 48 hours after adding granular CYA.
- Log the result — recheck monthly during swim season.
What is pool stabilizer (cyanuric acid)?
Cyanuric acid (CYA) protects chlorine from UV degradation. Without it, sunlight can destroy up to 90% of free chlorine in a few hours. Target range: 30–50 ppm for standard chlorine pools, 60–80 ppm for saltwater (SWCG) pools.
How much stabilizer do I need to raise CYA by 10 ppm?
For 10,000 gallons: about 1.3 lbs of pure (100%) cyanuric acid granular, 2.3 lbs of 56% stabilizer granular, or 0.43 gallons of 30% liquid stabilizer. Use the calculator above for your exact volume and target increase.
Can I add stabilizer directly to the skimmer?
Yes — granular CYA dissolves slowly. Pour it into the skimmer with the pump running, then let the pump circulate for 24–48 hours before backwashing. Do not backwash for at least 48 hours after adding.
What if my CYA is already too high (>100 ppm)?
Cyanuric acid does not evaporate or degrade significantly. The only practical fix is a partial drain and refill. Drain enough water to bring CYA back into range, then refill and retest after 24 hours of circulation.
Do dichlor and trichlor add stabilizer?
Yes. Dichlor adds roughly 0.9 ppm CYA per 1 ppm of free chlorine dosed. Trichlor adds about 0.6 ppm CYA per 1 ppm FC. If you use these as your primary sanitizer, your CYA will climb steadily — test monthly.
How often should I test CYA?
Monthly during swim season, and after any significant rain, refill, or partial drain. Use a drop-count kit (Taylor K-2006 or TF-100) — test strips are unreliable for CYA and can read 20+ ppm off at high stabilizer levels.