Stabilizer (CYA)
Protect your chlorine from UV degradation by maintaining proper Cyanuric Acid levels.
Target Range
What Is Stabilizer?
Stabilizer, also known as Cyanuric Acid (CYA), acts as a "sunscreen" for your free chlorine. Without it, the sun's powerful UV rays will degrade and destroy your chlorine in a matter of hours, leaving your pool unsanitized and unsafe.
How to Add Stabilizer
Granular stabilizer is very slow to dissolve and can sit on the pool floor, damaging liners. The best method is to pour it into a "skimmer sock" or pantyhose and place it in the skimmer basket. Squeeze it occasionally until fully dissolved. Avoid backwashing for 48 hours after adding.
Chlorine Stabilizer
Cyanuric Acid (CYA) for UV protection.
Low Stabilizer Effects
If CYA is below 30 ppm, you will burn through chlorine rapidly. You might find yourself adding gallon after gallon of bleach with zero reading the next day. This gets expensive quickly and leaves your pool vulnerable to algae blooms during the sunny afternoon hours.
Maintenance Tip
Unlike chlorine, stabilizer does not get "used up". It stays in the water indefinitely. The only way it lowers is by draining the pool, backwashing, or heavy splash-out. Test CYA monthly to ensure you haven't drifted too high or too low.
Pool Water Test Kit
Professional test kit.
High Stabilizer (Chlorine Lock)
When CYA gets too high (typically > 100 ppm), it over-stabilizes the chlorine, binding to it so tightly that it cannot release to kill bacteria. This is called "Chlorine Lock". At this stage, no amount of chlorine will clear a green pool; you MUST drain water to lower the CYA.
Chlorine with Built-in CYA
Be careful with "Trichlor" pucks and "Dichlor" shock powder. These are ~50% stabilizer by weight. Every time you use them, your CYA level rises. This is the #1 cause of "Chlorine Lock" in residential pools. Switch to liquid chlorine if your CYA is getting high.
Go Pro with Mobile
Protect your chlorine investment. Track stabilizer levels and prevent chlorine lock with our advanced mobile tools.
Expert Pool Care Articles
Stabilizer 101
Understanding the importance, testing options, and chemicals for balanced pool water.
The Role of CYA
A comprehensive guide on Cyanuric Acid and its role in pool maintenance.
Fix Low Chlorine
Troubleshoot why your chlorine levels might be constantly low (often CYA related).
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