Why We Sometimes Skip the Chlorine Tabs in Your Floater
By Nancy Padjan | 3 min read
We've been getting this question a lot lately, so we figured it was time to write it down: why is there nothing in my floater? It's a fair question, and the answer almost always comes down to one number on your water test. That number is cyanuric acid. When CYA is already high, adding more tablets makes the problem worse, not better. Here's the short version of what's going on.
What CYA Does and Why Tablets Are a Problem
Cyanuric acid (CYA), also called stabilizer, protects free chlorine from being destroyed by UV light. Without it, the Fresno sun burns off chlorine within hours. The ideal range is 30 to 50 ppm for chlorine pools, or 60 to 80 ppm for saltwater. Above 100 ppm, chlorine becomes so tightly bound to the stabilizer that it loses much of its sanitizing power.
Here's the catch: standard 3-inch chlorine tablets (trichlor) contain both chlorine and CYA built in. For every 10 ppm of free chlorine they add, they also add about 6 ppm of CYA. That CYA doesn't break down or evaporate. Over a Fresno summer with tabs running day and night, a pool starting at 40 ppm in May can easily hit 120 to 150 ppm by August.
Why That Matters in July and August
When CYA gets too high, your chlorine stops working efficiently. At 30 ppm CYA, 2 ppm of free chlorine is plenty. At 100 ppm CYA, you need 7 or 8 ppm to do the same job. And this is exactly when algae shows up. A high-CYA pool with underperforming chlorine in Fresno heat is an algae bloom waiting to happen, and harder to clean up than to prevent.
What We Do Instead
When CYA is already at or above the threshold, we switch your chlorine source. Instead of tabs, we use liquid chlorine (sodium hypochlorite) added directly during service. Liquid chlorine adds no CYA. It's pure sanitizer.
This means:
The floater stays empty until CYA comes down to a workable range
Chlorine drops faster between visits since there's no continuous dissolving source
We may recommend you supplement with liquid chlorine between visits during heat waves
Putting more tabs in would feel like we're doing more, but it would actively make the chemistry worse.
Why We Can't Just Drain Some Water
Normally, the fix for high CYA is a partial drain and refill. In Fresno, it's more complicated. Per Fresno Municipal Code Section 6-520(a)(16), pools can't be drained more than once every three years without supporting documentation, and every drain requires a Short-Term Exemption Permit filed 48 hours in advance. High CYA is recognized in the code as a qualifying reason, but the permit process takes time, paperwork, an independent water test, and water costs of $100 to $200 per refill.
For the full drain process, see our post on how long a pool drain and refill takes in Fresno.
Bottom line: preventing high CYA by switching off tabs at the right time is much easier than draining to fix it later.
The Bottom Line
So to anyone who has asked us about the empty floater recently: thank you for paying attention to your pool, and now you know. An empty floater isn't us cutting corners. When your CYA is already high, adding tabs would make a real problem worse. Liquid chlorine is the right tool, even though it's not the most convenient one. If you ever have questions about what we did or didn't add during a service visit, ask. We'll show you the numbers and explain the reasoning.
This post is for general informational purposes and reflects Fresno water rules and pool chemistry practices as of the publication date. Municipal codes, water conservation stages, and city schedules can change. Always verify current rules with the City of Fresno Water Division before applying for a permit or scheduling a drain. Every pool is different, and the right chemical approach depends on its construction, age, equipment, and current water chemistry. Nothing in this post is a substitute for an on-site assessment by a licensed pool professional.
NTS Pool Services is a locally owned pool care company based in Fresno, CA. We provide weekly pool service, green pool cleanup, drain and restart, filter cleaning, pool repairs, and chemical balancing throughout Fresno and the Central Valley. Contact us for a quote.