How do I lower cyanuric acid?

Drain and refill part of the water — the calculator shows the percentage. A reverse-osmosis mobile service is the no-drain alternative.

What CYA is too high?

Above ~100 ppm for a chlorine pool (or ~100–120 for saltwater). At that point chlorine loses too much punch.

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Lower Pool CYA Calculator

There's no chemical that lowers cyanuric acid — only dilution. Enter your current and target CYA to see how much water to replace.

Balance your whole pool at once →Enter all your readings on one screen and get an ordered dosing plan — the full Water Report.

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Paste it anywhere on your site. It includes a small credit link back to the full tool.

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<p style="font:13px system-ui,sans-serif;margin:6px 0 0">Free <a href="https://poolchemlab.com/pool-cya-reducer-calculator/">Lower Pool CYA Calculator</a> by <a href="https://poolchemlab.com/">PoolChemLab</a></p>

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How to use it

Test your CYA.
Enter your current level, target, and volume.
Lower the water by the shown percentage and refill with fresh water; re-test once mixed.

Why you can only dilute CYA

Cyanuric acid doesn't break down or get consumed, and nothing on the market removes it chemically. The only ways down are replacing water (drain & refill) or a reverse-osmosis service that filters it out. High CYA (over ~100 ppm) makes chlorine sluggish, which is why pools with too much stabilizer struggle to stay clear.

For the full walkthrough — what's too high, how it got there, and how to stop it climbing — see how to lower cyanuric acid →.

Frequently asked questions

How do I lower cyanuric acid?: Drain and refill part of the water — the calculator shows the percentage. A reverse-osmosis mobile service is the no-drain alternative.
What CYA is too high?: Above ~100 ppm for a chlorine pool (or ~100–120 for saltwater). At that point chlorine loses too much punch.

Related calculators & guides

Built & reviewed by a working pool-service pro. Target ranges follow CDC MAHC, PHTA, and Taylor guidance. Doses are starting estimates — add a little less than the max, re-test, and confirm against your product label. Educational tool, not a substitute for a water test or professional advice.