Why High Cyanuric Acid (CYA) Levels Can Wreck Your Pool Water

And Why Draining May Be the Only Solution for Sacramento Valley Pools

If you’re a pool owner in Sacramento, Davis, Woodland, or anywhere in the Sacramento Valley, you’ve likely heard the term CYA — short for cyanuric acid. But what is it really, and why is it causing problems in so many backyard pools?

As a trusted local pool service company, we get this question all the time:

“Why can’t we just treat the water?”“Do I really have to drain my pool to fix high CYA?”

Let’s break it down.

What Is Cyanuric Acid (CYA) and Why Is It in Your Pool?

Cyanuric acid is a stabilizer or conditioner used to protect chlorine from being destroyed by UV rays from the sun. In sunny places like Sacramento County and Yolo County, it’s essential — without CYA, your chlorine can evaporate in just a few hours.

Here’s the catch:

CYA doesn’t evaporate or break down. It builds up over time — especially if you:

• Use dichlor or trichlor tablets

• Rarely drain or dilute your pool

• Keep adding stabilized shock or tablets

What Happens When CYA Levels Get Too High?

When CYA levels exceed 100 ppm, it starts to reduce chlorine’s effectiveness. In other words: You can have the right amount of chlorine in the water — and still get algae or cloudy water.

High CYA can cause:

• Persistent algae growth despite regular shocking

• Chlorine lock (where chlorine is present but non-functional)

• Cloudy or dull water

• Increased chemical costs (because chlorine becomes less effective)

• Irritated eyes and skin

• Dangerous false sense of safety

Pools in hot regions like Woodland, Davis, and Folsom are especially vulnerable because high sun exposure burns off chlorine — but the CYA stays behind, compounding the issue.

Can You Treat High CYA Chemically?

Short answer: not really.

There are some enzyme-based products on the market that claim to reduce CYA — but:

• They’re expensive

• Results are inconsistent

• They take weeks to months to work — if they work at all

So what’s the real fix?

Draining (or Partial Draining) Is the Only Reliable Solution

To reduce CYA to a safe, manageable level (30–50 ppm for non-salt pools), you need to physically remove water from the system and replace it with fresh, untreated water.

This can involve:

• A full drain and refill

• A partial drain (e.g., 25–50%) if CYA isn’t extremely high

• Using subsurface drains for safer, controlled water removal

In many Sacramento Valley homes, especially older pools or ones with heavy tablet use, we’ve seen CYA levels over 200+ ppm — which nearly eliminates chlorine's sanitizing power.

What’s the Best CYA Level for Sacramento Valley Pools?

• Chlorine pools: 30–50 ppm

• Saltwater pools: 60–80 ppm

• Anything above 100 ppm? Time to consider draining.

And if your pool is struggling to stay clear even though your chlorine is perfect, CYA may be the hidden culprit.

Regular CYA Testing = Long-Term Pool Health

In the Sacramento Valley’s hot, sunny climate, testing CYA levels at least once per month during the swim season is key.

Our team at Provident Pools includes CYA testing as part of every other weekly maintenance visit, so you’re never left in the dark.

We Fix High CYA Problems Across Sacramento, Davis, Woodland & Beyond

Our trained techs can:

• Test and report your current CYA levels

• Recommend partial or full pool draining

• Handle the drain + refill process safely

• Balance your water chemistry afterward

• Offer tablet-free chlorine alternatives to avoid future buildup

We proudly serve pool owners in:

• Sacramento

• Davis

• Woodland

• Folsom

• Roseville

• Rocklin

• Citrus Heights

• And the entire Sacramento Valley

Don’t Let High CYA Destroy Your Pool Chemistry

CYA is necessary — but too much of a good thing can make your pool unsafe and unstable. If you suspect high stabilizer levels, cloudy water, or chlorine that just isn’t working — it’s time to take action.

📞 Call Provident Pools at 916-954-1909

or

💧 Schedule your pool evaluation at www.providentpools.com

Let’s get your water clean, clear, and balanced — the way it should be.