When it comes to pool chemistry, most people focus on pH and chlorine — but total alkalinity is the...
What Is Pool Stabilizer? (And Why Your Chlorine Needs It!)
You’ve tested your pool, added chlorine, and everything looks great… until your chlorine disappears overnight. What gives?
Chances are, your pool is missing a critical ingredient: stabilizer .
Also known as cyanuric acid (CYA), stabilizer is like sunscreen for your chlorine — and without it, your sanitizer gets burned off by the sun before it can do its job. Let’s break it down:
☀️ What Is Pool Stabilizer?
Pool stabilizer is a chemical (cyanuric acid) that helps protect chlorine from being destroyed by the sun’s UV rays. Without it, up to 90% of your chlorine can evaporate in just a few hours on a hot day.
Think of it like this:
> Chlorine fights germs. Stabilizer fights the sun.
When your pool has the right amount of stabilizer, your chlorine lasts longer, works more effectively, and keeps your water cleaner.
✅ Ideal Stabilizer Levels
Recommended range: 30–50 ppm for chlorine pools
- Too low < 20 ppm): Chlorine burns off too quickly
- Too high > 100 ppm): Chlorine becomes less effective, can lead to cloudy water or algae
💡 Note: If you have a saltwater pool, aim for 60–80 ppm of stabilizer.
⚠️ Signs Your Pool Needs Stabilizer
- Chlorine levels drop quickly, even after shocking
- Algae growth despite proper chlorine dosing
- Cloudy water after a few sunny days
- There is a frequent need to add more chlorine than usual
🧪 How to Test Stabilizer Levels
You can test stabilizer (CYA) with:
- A liquid test kit that includes CYA
- Test strips labeled for stabilizer
- A professional water test at your local pool store
🔁 What If Your Stabilizer Is Too High?
Too much CYA can reduce chlorine’s effectiveness, making it harder to fight algae and bacteria.
⚠️ Caution: Adding too much stabilizer can cause “chlorine lock” — where chlorine is present but ineffective.
Unfortunately, there’s no chemical to lower the stabilizer. You’ll need to: Partially drain and refill your pool with fresh water.
🏁 Final Thoughts: Balance Is Everything
Pool stabilizer might not get as much attention as chlorine or pH, but it plays a huge role in keeping your water clean and clear — especially under the summer sun.
So next time your chlorine isn’t holding, don’t just add more — check your stabilizer. It could be the missing piece of your pool care puzzle.
Need help testing or balancing your pool’s stabilizer? Stop by or give us a call — we’ve got the tools, products, and advice to keep your pool crystal clear and swim-ready.
