Hey, Tom Clow here from Float On Pools & Spas. This time of year, as we're heading into swim season here in Volusia and Flagler counties, I get a lot of calls from pool owners who are frustrated. Their salt system is running, their chlorine reads fine in the morning, but by afternoon the water looks off. Maybe a little hazy. Maybe the chlorine has dropped dramatically. And they can't figure out why.
Nine times out of ten, the answer is the same thing: their CYA is either too low, completely depleted, or was never added after their last water change or heavy rain dilution. It's the most overlooked chemical in pool care, and for salt pool owners specifically, it's absolutely critical.
What Is CYA and What Does It Actually Do?
CYA stands for cyanuric acid, and it goes by a few names: conditioner, stabilizer, or sometimes just "stabilizer." It's a chemical compound that acts as a sunscreen for your chlorine. That's the simplest way I know to explain it.
Here's the science behind it. When your salt system generates chlorine through electrolysis, it produces free chlorine (hypochlorous acid) in the water. That chlorine is what kills bacteria, algae, and other contaminants. It's doing its job. The problem is that ultraviolet radiation from sunlight breaks down free chlorine extremely fast. We're talking about losing up to 90% of your chlorine within two hours of direct Florida sun exposure if there's nothing protecting it.
CYA bonds loosely with free chlorine molecules and essentially shields them from UV degradation. The chlorine is still active and still sanitizing, but it's protected from being burned off by the sun. Without CYA in your water, your salt system has to work overtime just to keep up with the sun's destruction of chlorine, and in many cases, it simply can't keep pace. You end up with a pool that looks fine at 7am and is swimming in algae by the weekend.
Why Salt Pool Owners Need to Pay Extra Attention
Here's where it gets interesting, and where a lot of pool owners get tripped up. Traditional chlorine tablets (trichlor) actually contain CYA built right into them. Every time you drop a tablet in a floater or feeder, you're adding a small amount of stabilizer along with the chlorine. Over time, CYA levels in traditionally chlorinated pools can actually get too high.
Salt pools are different. Your salt chlorine generator produces pure chlorine with no stabilizer attached. That means your CYA level only goes in one direction over time: down. Rain dilutes it. Backwashing removes it. Partial water changes drop it. And Florida sun destroys the chlorine it was supposed to be protecting.
I've tested pools in Ormond Beach and Palm Coast where the CYA was sitting at zero. The homeowner had no idea. Their salt system was running at 80% output trying to compensate, burning through the cell faster than normal, and the pool was still struggling to hold a chlorine reading past noon. Once we added the proper amount of CYA, the pool stabilized within 48 hours and the salt system dropped back to a normal 40-50% output. The cell will last longer, the pool will stay cleaner, and the chemistry will be far more predictable.
What's the Right CYA Level for a Salt Pool?
This is where you need to be precise. For salt pools specifically, the recommended CYA range is 70 to 80 ppm (parts per million). This is slightly higher than the 30 to 50 ppm range often recommended for traditionally chlorinated pools. The reason is that salt systems produce chlorine continuously at lower concentrations, and that chlorine needs more protection to remain effective throughout the day.
Going below 50 ppm in a salt pool means your chlorine is getting hammered by UV and your system is working harder than it needs to. Going above 100 ppm creates a different problem: the CYA actually starts to over-bind with the chlorine, making it less effective at sanitizing. This is called chlorine lock, and it's a real issue. You can have a chlorine reading of 3 ppm but the water is still not being properly sanitized because the CYA has essentially tied up all the active chlorine.
The sweet spot for salt pools in our Florida climate is right in that 70 to 80 ppm range. Not too low, not too high.
Why Right Now Matters: The Swim Season Window
We're heading into the time of year when pools in Volusia and Flagler counties go from occasional use to daily use. Water temperatures are climbing. UV intensity is increasing. And families are getting ready to actually swim in these pools.
This is exactly the wrong time to have depleted CYA. Here's why. When pool water is colder and usage is lower, the consequences of low CYA are less immediately obvious. Chlorine still gets burned off, but slower water temperatures mean slower algae growth, so you might not notice the problem right away. But once the water hits 80 degrees and kids are splashing around every afternoon, a pool with no CYA protection can turn green in a matter of days.
I've seen it happen. A pool that looked perfectly fine in February is a swamp by Memorial Day weekend because the owner never checked their CYA after winter rains diluted it down to almost nothing.
The smart move is to test your CYA right now, before swim season is in full swing. If it's below 60 ppm, add conditioner. If it's been more than six months since you added any, add conditioner. If you've had significant rainfall or recently topped off your pool with fresh water, test and likely add conditioner.
How to Add CYA to Your Pool
Cyanuric acid comes in granular form and it dissolves slowly. Unlike chlorine shock, you don't just toss it in and walk away. The proper method is to pre-dissolve it in a bucket of warm water first, then pour it slowly in front of a return jet with the pump running. This helps distribute it evenly and prevents it from sitting on the pool floor and potentially bleaching your surface.
The dosing calculation is roughly 13 ounces of granular CYA per 10,000 gallons of water to raise levels by 10 ppm. So if you have a 15,000 gallon pool and your CYA is reading 40 ppm, you'd need to raise it by 35 ppm, which works out to about 68 ounces, or just under 4.5 pounds of conditioner.
One important note: CYA does not dissipate on its own. Once it's in the water, the only way to lower it is to dilute the pool water. So add it carefully and test before adding more. We always recommend testing 24 to 48 hours after adding CYA to get an accurate reading, since it takes time to fully dissolve and distribute.
A Word About Your Overall Water Balance
While you're checking CYA, this is also a great time to look at your overall water chemistry before swim season. For salt pools, you want your free chlorine between 2 and 4 ppm, your pH between 7.4 and 7.6, and your total alkalinity around 80 to 100 ppm. Salt pools tend to push pH higher over time due to the electrolysis process, so keeping alkalinity on the lower end of that range (closer to 80 ppm) gives you a lower "pH ceiling" and makes the water easier to manage. This also helps maintain a balanced LSI (Langelier Saturation Index), which protects your pool surface from scaling or etching.
Your salt level should be in the range your manufacturer recommends, typically 2700 to 3400 ppm depending on the system. And your calcium hardness should be between 200 and 400 ppm to protect your salt cell and pool surface.
Getting all of this dialed in before the first big swim weekend of the year is the difference between a pool you're proud of and a pool you're embarrassed by.
When to Call a Professional
If you're not sure where to start, or if your pool has been sitting without proper chemical maintenance over the winter, a professional water analysis is the smartest investment you can make right now. A proper test goes beyond the basic strips you buy at the hardware store. We test for CYA, calcium hardness, total dissolved solids, phosphates, and a full chemistry panel that gives us a complete picture of what your water needs.
At Float On Pools & Spas, we service pools across Ormond Beach, Daytona Beach, Palm Coast, Flagler Beach, and the surrounding areas. If your salt pool hasn't been professionally serviced since last fall, or if you're not confident in your current chemistry, give us a call before swim season hits full stride. Getting your CYA right is one of the single most impactful things you can do for your pool this spring, and we're here to help you get it done right.