Bob Lowry on the Dangers of High CYA Levels

Your pool water can look “chlorinated” on a test and still be unsafe or algae-prone. The missing piece is cyanuric acid (CYA), the pool stabilizer that quietly binds most of your chlorine and changes how much active sanitizer you actually have working for you. We sit down with Bob Lowry, inventor of liquid pool conditioner, to get brutally clear on why high CYA is a real problem and how to fix it without guessing. 

We dig into what cyanuric acid really does beyond UV protection, how the chlorine to CYA equilibrium works, and why the same free chlorine reading can mean totally different sanitizing power depending on your stabilizer level. Bob lays out an easy operating rule for pool maintenance: target free chlorine as a percentage of CYA, with different guidance depending on whether you use borates. If you’ve ever fought recurring algae, this is the chemistry that explains why. 

We also connect the dots to the most common cause of runaway stabilizer: trichlor tabs. When CYA rises week after week, the required chlorine level rises with it, creating a vicious cycle that catches a lot of pools in midsummer. We cover practical ways to transition to liquid chlorine, plus simple feeding options that keep levels steady between service visits. If this helped, subscribe, share it with a pool owner who keeps battling algae, and leave a review. What’s your current CYA level and how are you chlorinating right now?

We break down why high cyanuric acid quietly weakens chlorine and forces you into higher and higher dosing just to prevent algae. Bob Lowry explains the real stabilizer to chlorine relationship, plus simple target ranges and practical ways to stop CYA from spiraling out of control.  
• why cyanuric acid does more than block sunlight  
• how CYA binds chlorine and slows sanitizing action  
• the 7.5% of CYA chlorine target without borates  
• the 5% of CYA chlorine target with borates  
• recommended CYA ranges for outdoor pools and saltwater chlorine generators  
• why trichlor tabs raise CYA and create a vicious cycle  
• switching to liquid chlorine and options for midweek dosing  
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Transcript

SPEAKER_00 0:15

Welcome to the Festival Fooling podcast show. Bob Lowry will be talking today about high cycleic acid and why highsteineric acid in a pool really is a problem. Now there's of course a debate on both sides of the argument, but I think Bob Lowry is the expert in the industry or was the expert in the industry. And here you can hear him talk about why highsteineric acid is a problem in pool. Are you a full service pro looking to take your business to the next level? Join the pool guy coaching program. Get expert advice, business tips, exclusive content, and get direct support from me. I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at swimmingpoollearning.com. You're the inventor, I don't know if we mentioned that, but you're the inventor of liquid pool

Welcome And Today’s Pool Problem

SPEAKER_00 1:03

conditioner. Natural chemistry sells that. And so you know a lot about cyaneric acid, of course, from that. And I I strictly use liquid conditioner. I love that product. Even though it's more expensive, I know that it's bulletproof as far as the side effects of the other one. We'll talk about that too later in this recording. But what is a good cyaneric acid level? And why is cyaneric acid even important to have in the pool?

SPEAKER_01 1:28

Well, cyanuric acid, we used to think that cyanuric acid all it did was protect uh chlorine from sunlight. But cyanuric acid actually works as a buffer against the pH going down. It controls the amount of chlorine that's available in the pool to kill things. And and we the information has been around for a long time, but we haven't drilled down to the part of you know actual use practicality of it. But the fact of the matter

What Cyanuric Acid Really Does

SPEAKER_01 2:08

is, if you have any more than 30 parts per million of cyanic acid in the water, 97% or more of your chlorine is bound to that cyanoric acid. Now it doesn't mean that it's not available, it means it's bound to it, and 3% is available right now. If that 3% gets used, then it gets replaced from the 97%. And it keeps getting replaced, but it keeps that 97 and 3% ratio, it keeps that equilibrium ratio maintained. So the more cyanuric acid you have in the water, the more it slows down the chlorine. The as you get really high, it ties up most of the chlorine, and you need even more chlorine to get to get an amount of chlorine that's a that's enough to prevent algae and bacteria in the pool. And we've done a lot of calculations to be able to simplify all of those calculations. And what it came down to is that we recommend, I recommend, that you keep a chlorine level that is 7.5 percent of your cyanuric acid buffer, and that is in a pool without boring in it. So it's 7.5 percent of CYA. And you can then see pretty quickly if you get up to 100 parts per million of cyanic acid, you'd need 7.5 parts per million of chlorine. And nobody wants to keep that amount of chlorine in the pool. But that's what you need to prevent algae. And and so if you keep a lower level, say at 50, then you would need 7.5 times

The 7.5% Rule For Chlorine

SPEAKER_01 4:06

50, which is about 3.5 or 4 parts per million. So it still is a little bit high. But if you put 50 parts per million of chlorine in the pool, you will only need a chlorine level that is 5% of cyanuric acid. And so you could go all the way to 100 parts per million of cyanuric acid, still only need five parts per million of chlorine in the pool.

SPEAKER_00 4:31

That's interesting.

SPEAKER_01 4:33

So, and if you have 50 parts per million in the pool, you can put 2.5 parts per million of chlorine in the pool and prevent algae and bacteria. And we could do the calculation. The the if you take, for instance, if we know that 3% of chlorine is available, and we know that of that 3%, you have seen for years, I'm sure, you've seen that when you put chlorine in water, you make HOCL and OCL minus, the killing form and the non-killing form of chlorine. And at pH 7.5, you have about 50% of each. So what that means is that that if you have 3% of the chlorine in the water is not bound to cyanric acid, then 50% of that or 1.5% is HOCL. And we know that it takes 0.05 parts per million of HOCL to kill algae. And algae is harder harder to kill than bacteria. So if we kill algae, we've automatically kill the bacteria. But using those numbers, we can calculate whether or not we can kill the algae. And so if we have two parts per million of chlorine in the pool, and only 1.5 of it is HOCL, 1.5%. If you take 1.5% of two, you come up with 0.03 parts per million HOCL. And I just finished telling you we need 0.5 parts per million HOCL to kill the algae. So two parts per million won't do it. And if you take three parts per million times 1.5 percent, you come up with 0.45, and that's right at the edge of killing algae. You technically need 0.05, and that's 0.045, so you're close. And if you take four parts per million, for instance, four times 1.5 percent is 0.6 parts per million HCL. So we know whether or not you've got enough algae in the pool to kill anything, and and instead of doing that calculation all the time, we can tell you it's 5% if you use borate or 7.5 percent of CYA if you're not gonna use borate. And that's a real easy way to know how much chlorine to put in the pool. And if you do that, the advantage of it is that you're not gonna have any algae, period. And the you will use less chlorine because the chlorine that's in the water doesn't have to kill the algae when it starts to grow, because borate's doing that. So you will be using less chlorine if you use borate. Your chlorine generator will run less if you use borate because you don't need as much chlorine. So there are those advantages to doing that. So the proper level for cyanuric acid is between 30 and 50, and 50

Borates, Better Ratios, Better Results

SPEAKER_01 8:02

is probably better. But and that has to do with sunlight degradation. But the only asterisk to that is if you have a chlorine generator. And my recommendation for when you have a chlorine generator is to use 70 parts per million of cyanuric acid. And the reason for that is that in where you are making chlorine, there's a high concentration of chlorine in the water, and it can use up all of the cyanuric acid. And when it uses up all of the all of the cyanuric acid, then you have chlorine going back to the pool that's unprotected from sunlight. And sunlight degradation is very fast. And so as the water, you know, and the chlorine returned at the surface where the sun is the stronger, the rays of the sun are the strongest. So when we put the if there's chlorine coming out of the return line that's unprotected, it can get zap pretty quick by the sunlight. So one higher level, so that all the chlorine that's made gets protected by cyanuric acid.

SPEAKER_00 9:14

That makes a lot of sense. And if you know someone can probably replay that and listen to the numbers again, because you're just doing this off the top of your head, um, which is pretty amazing watching you do this, you know. But so a pool that has like 200 or 300 parts a million, now you can see the problem with that cyaneric acid level so high, because then if you use that seven uh percent, you can either have a pretty large amount of chlorine in there, the parts per million, in order to prevent algae growth. And that's why you see a lot of yeah.

SPEAKER_01 9:44

If if you had 200 parts per million of cyanuric acid in your pool, you need 15 parts per million of chlorine. And so you can see, and and that leads us to the problem of using trichlor, because you can see the the number is this that for each 10 parts per million of trichlor, you of chlorine you put in the pool using trichlor, you put in six parts per million of cyanuric acid. And most pools

Trichlor Raises CYA And Fuels Algae

SPEAKER_01 10:14

in a week use about in the summer use about 10 parts per million of chlorine. So your cyanuric acid is gonna go up by six parts per million per week. So in a month it's gonna go up by 25. So in a month it's gonna go up by 25. And if you keep the chlorine level where you kept it last month, you're gonna have algae. So you need to add more chlorine because now your cyanuric acid level is higher.

SPEAKER_00 10:44

Yeah, so it's a vicious cycle, basically.

SPEAKER_01 10:46

You know, and then it's just a vicious cycle. And you know, cyanuric acid builds up, you have to put more chlorine in. Put more chlorine in, the cyanuric acid builds up. And it just creates that vicious cycle. So, what I recommend is maybe using trichlor until you get to 50 parts per million and then switch to using liquid chlorine. And liquid chlorine, the only problem that that there is with liquid chlorine is that the you may not be able to put in enough to last for a week because you'd have to put in 10 or 12 parts per million of chlorine for a week. And that means that on the day you're there, the chlorine level may be pretty high. So you don't really want to do that. The option then is to leave a gallon of chlorine or a half gallon or whatever with the homeowner and ask them in the middle of the week to add it. The other thing that you can do is put in a liquid chlorine dispenser, and one company

Switching To Liquid Chlorine Dosing

SPEAKER_01 11:44

makes one, uh, Hasa makes one that's called the liquidator. That's a tech of chlorine with a valve on it. And other people use like a roller cam or a stinner or one of those peristaltic pumps, and they they dispense an amount of chlorine into the pool that's equal to about one part per million per day. And that's the same as using a trichlor feeder and adjusting it so you got some chlorine when you come back at the end of a week.

SPEAKER_00 12:13

If you're looking for the podcast, just go to my website, swimming for learning.com. On the banner's a podcast icon. There'll be a drop down menu with over 1900 podcasts for you there to listen to at your leisure. And if you're interested in the coaching program, you can learn more at poolguycoaching.com. Thanks for listening to this podcast. Have a rest of your week. God bless.