Cyanuric Acid: The Most Misunderstood Chemical in Pools

Rudy dives headfirst into cyanuric acid — CYA, stabilizer, conditioner — the most misquoted, weaponized, and argued-about chemical in the pool industry. He breaks down what the science actually says about HOCl in stabilized water, why that old HOCl / OCl⁻ chart belongs in a museum, how CYA really impacts ORP, TA, and LSI, and why “chlorine lock” is less supernatural curse and more “you nuked the stabilizer and fed the biofilm.”

Between the chemistry deep dive, Rudy hits the global pool-industry newswire: PHTA’s APSP-11 rewrite, bromate and sodium bromide drama, media consolidation across major trade mags, massive international trade show attendance, European trends in energy-efficient builds, Australian code delays, and South American market movement. If you’re running a pool business in 2025, this episode hits both your test kit and your bottom line.

In This Episode

• CYA: Not the Villain, Not the Hero, Just Misunderstood
  Why cyanuric acid became “chlorine’s sunscreen,” how chlorinated cyanurates actually work, and why CYA got popular in the first place — because it works, not because a committee was bored in the ’60s.
• Why the Classic HOCl Chart is Garbage in Stabilized Pools
   
• Real HOCl Percentages at Common CYA Levels
   
• Copper Cyanurate Stains & “Prom Night Blue” Plaster
   
• CYA, Total Alkalinity & LSI: The Secret Sabotage
   
• ORP Suppression & Why Stabilized Pools Read “Low”
   
• Chlorine Lock is a Myth
   
• The Holy Sh*t Zone: CYA at 300 ppm and Up
   
• Alum Method to Lower CYA – How to Do It Right
   
• Fecal Incidents, CYA, and the Law (CDC Crypto Protocols)
   
• Does CYA Really Buffer pH? The Honest Answer
   
• Best-Practice CYA Targets
   

Global Trade Magazine News Roundup

Rudy also runs through the week’s biggest stories from around the world:

• PHTA’s APSP-11 Water Quality Standard Rewrite
   
• Record Global Attendance at the 2025 PSP/Deck Expo in Vegas
   
• Pool & Spa News – Top 50 Service Survey
   
• AQUA Magazine’s 50th Anniversary Preview
   
• Service Industry News – United Chemical Bromate Study
   
• Kenilworth Media’s Big Acquisition Move
   
• EuroSpaPoolNews – Barcelona & Germany Specials
   
• SPLASH! Magazine – NCC 2025 Delay in Australia
   
• Brazil – Revista da Piscina & Pool Life
   

Transcript

Rudy (00:00)
So if I told you that there was a chemical in your pool that could save you literally thousands of dollars in chlorine, but at the same time, if you ignore it, could cripple your sanitizer effectiveness,

on prom night and quietly push your water into corrosive territory while every test strip is lying to your face telling you, hey, this shit looks good. You probably wanna know what chemical I'm talking about, right?

Rudy Stankowitz (01:50)
Welcome to Friday. I'm Rudy Stankiewicz. This is the Talking Pools podcast and today a topic that is almost guaranteed to always cause some heated debate between pool professionals. That's right. I'm talking CYA, cyanuric acid.

Rudy (02:16)
So, cyanuric acid, hell, you might even be overdosing the crap out of it right now.

Your chlorine moves like it's stuck in molasses, your heater's crying copper tears, and the CDC treats it like kryptonite during a diarrhea accident. That chemical is cyanuric acid. Not the villain, not the hero.

just simply misunderstood, misquoted,

and over dramatized troublemaker in the entire swimming pool industry. So today I'm going to tell you why that old H O C L chart you keep worshipping belongs in the trash. Why the 90 part per million limit isn't some magical threshold, but a number of the industry landed on because nobody trusts techs with the dilution test and how

just adding a little extra stabilizer turns into a full blown forget about it situation before you even finish the route. We're driving straight into the stabilizer rabbit hole. But first, breaking news.

Let's hit the headlines.

First stop, Pool Magazine. PHA has officially completed its revision of the ANSI APSP ICC-11 public pool and spa water quality standard. And that draft is now out for public review. This update reorganizes key sections, but keeps core parameters intact.

And PHA is actively asking operators, builders, service pros and health officials to weigh in before December 8th, which just happens to be the birthday of Jim Morrison, Jim Morrison of the doors,

which means the people actually running pools have a chance to shape the rules that they'll be judged by. In that same issue, Pool Magazine is also reporting that the International Pool Spa Patio Expo in 2025

in Vegas hit record breaking global attendance, drawing pros from 40 countries and putting a huge spotlight on energy efficiency, automation and education under the PHA banner. reports I got back from folks that attended the show and folks that displayed at the show was that it was slower than usual. So what the article is saying though,

largest global attendance it's ever had, meaning people that have come over from other countries just to go to this show. I know you know that, I'm just saying it again. Anyway, to get the full details and timelines on the standards rewrite and the expo recap, read the full coverage in Pool Magazine. Next up, Pool and Spa news.

Their latest top 50 service survey just dropped and it's basically a snapshot of where the best performing service companies say the industry is heading. The headline, most of the top 50 are still seeing growth in accounts and revenue, but profit is getting squeezed with rising cost, price resistance and marketing spend all reshaping the battlefield. Consolidation is creeping in too, but a solid majority are still fiercely independent, even as many plan acquisitions or new branches in 2026.

for the full breakdown on margins, growth expectations, consolidation attitudes, check out the 2025 Top 50 Service Survey in Pool and Spa News. Over at Aqua Magazine, the big story is Aqua itself. The publication is gearing up to celebrate its 50th anniversary in 2026 in a feature looking back at its roots as Spa and Sauna in the 1970s, Southern California.

Editor Scott Webb traces how long the mag grew alongside the hot tub and pool bloom to become one of the most influential voices in the industry. It's part history lesson part love letter to the builders, retailers and service pros who've kept this trade alive through five decades of ups downs and you want it done by when jobs.

to read the full anniversary piece and to see how our industry got from water beds to wifi automation, head over to Aqua Magazine.

Now to Service Industry News. The top of the page this week is a deep dive on United Chemical's bromate study, the field investigation that's been sitting at the center of the sodium bromide in outdoor pools

and according to SIN's coverage, the findings may drive a serious regulatory reckoning as EPA label changes

formation get scrutinized against real world

pool conditions. If you wa on how we got from a for use in outdoor pools

North of the border,

spa marketing is carrying a story that hits the media side of our industry. Kenilworth Media, the Canadian publisher behind pool and spa marketing and Piscines and Spas has acquired three major US titles, Pool and Spa News, Aquatics International, and the commercial pool professional brand. The deal effectively consolidates a

chunk of North American pool media under one roof with

Kenilworth saying the move will allow better alignment of editorial events and advertiser support across the continent. For the full breakdown on what that acquisition means for coverage advertisers, future industry events, read that article in Pool and Spa Marketing.

Jumping across the Atlantic, Euro Spa Pool News has rolled out a special Barcelona 2025 edition ahead of the Piscina and Wellness Barcelona show. If you've not gone to that show, you really should. I've gone to it a couple of times. It is very, very, very different than the shows you see in the States. Everything is more like a Macy's window display, but it's not just the displays. It's the people.

It's the attire, it's the whole ambiance of the situation. So I suggest if you do ever get the opportunity to go, please take it back to the Euro Spa Pool news story. The issue is packed with product launches, exhibitor previews and European market Intel with a strong focus on energy efficient equipment, smart control systems and sustainable construction practices. It's essentially the playbook for anyone heading to the Spanish show wanting to know

who's exhibiting what and which trends are driving the EU market into 2026. So for that full Barcelona special and a better sense of where European trends are heading, grab the digital issue from Euro Spa Pool News.

Euro Spa Pool News also has its special Germany 2025 bilingual issue out, tied to the Aquanel and FSB trade fairs in Cologne. That addition highlights new technologies in water treatment, wellness, public pool design, and commercial aquatics, with a particular emphasis on sustainability.

energy performance and design innovations emerging from German and wider European manufacturers. eyeing European spec trends, the Germany special is worth a read. Again, that's Eurospa Pool News. Down under, Splash Magazine is tackling a big compliance question. When the 2025 National Construction Code

will actually be released. An article by Chris Philpott flags that the NCC 2025, which includes sections relevant to pool and spa construction and safety, has been delayed, creating uncertainty for Australian builders and suppliers trying to plan around upcoming changes.

known, what's still up in the air, and how companies can avoid getting blindsided when the new requirements eventually drop.

so for the full analysis and timeline guesses, head to Splash magazine. Pascina is spotlighting its latest issue tied to connect. seen it's Brazil 2025. The current edition promotes.

the Sao Bernardo do Campo event

a key meeting point for Brazilian manufacturers, distributors and service companies from October 30th through November 1st, 2025. Okay, so now this is obviously in the past. The coverage highlights growing interest in automation, heating and wellness features in the Brazilian market and positions the show as a barometer for how fast the country's residential and commercial sectors are evolving. So being that this

has already taken place and this is the most recent news story I have from those folks. Grab their copy and gear up their next issue that comes out because it's gonna tell you how all of that went, how the show worked, how successful that show was. Again, the latest issue of Revista da Piscina or Pool Life. Grab that copy, grab the next one.

So also from the Brazilian market, Pool Life is running a content on aguas na muchoredad, essentially the role of swimmers in aquatics for older adults. The feature explores how structured aquatic exercise improves health and quality of life for seniors. And it quietly signals a growing business opportunity. Programs, facilities, and strategies tailored to the melo-horridad demographic.

its wellness, public health and market expansion all rolls onto one theme. That's

So to dive deeper into that aging and aquatics trend, read the full piece on Pool Life site. Pool and Spa Marketing back in Canada, relevant globally, Pool and Spa Marketing is also running a forward looking feature.

on the future of pool care, efficiency, innovation, and smarter water management. The article pulls together themes we're seeing everywhere. Smarter automation, water and energy efficient systems, better data from connected equipment, and how all of that is reshaping what good service looks like in the next decade. For service pros, it reads like a roadmap of where the technical and customer expectations are heading.

So you can read that full trend piece in pool and spa marketing. That's your global pool trade roundup for the week from standard rewrites to bro-mate battles to media consolidation, record trade show attendance and shifting code timelines. if any of those stories hit close to home for how you run your business, don't just take my word for it. Go read the thing. Go to the original reporting in the magazines we mentioned.

support the folks doing the journalism so the rest of us don't fly blind. We'll keep watching the wires.

but subscribe, get that news on a regular basis. Now, back to the most misunderstood, misquoted and argued about chemical in the entire industry.

I'm talking about cyanuric acid.

I'm talking about cyanuric acid.

CYA, stabilizer, conditioner, whatever name it's using this week, the white powder that looks harmless, acts complicated, and starts more fights than a Thanksgiving dinner with your in-laws. If you've been doing this long enough to get sunburned through a UPF shirt, you already know. CYA does not shut up. People argue about it like it owes them money. Half the myths out there came from this guy who trained me back in 98, quote unquote, and to this day,

Bigfoot has better documentation than cyanuric acid. So that's why we want to reset the whole damn thing real chemistry real history real explanations and yeah a Little bit of humor because what the fuck that's me and that's how we roll here And if you remember nothing else from this episode, remember this cyanuric acid is not the problem Misunderstanding cyanuric acid is the problem

didn't start off as a pool chemical. No, no, no, no, no. It was just an innocent industrial compound minding its own business until some genius chemist said, hey, chlorine capes getting roasted by the sun, what if we gave it sunscreen? And then boom, new purpose unlocked.

By the 60s, it's hanging out with trichlor and dichlor. By the 80s, it's everywhere. By the 90s, everyone has an opinion. By the 2000s, or the double-ots, forget about it. The misinformation is breeding faster than mustard algae in August. Today, CYA is basically a religion. Some love it, some fear it,

And some squint at that test vial like it's a magic eye poster and they're waiting for a dolphin to suddenly appear. But here's the simple truth. CYA got popular because it works. It protects chlorine by forming chlorinated cyanurates, little tiny body guards keeping HOCl, which is the active form of chlorine, The killing form from

sun burning off in 10 minutes without

chlorine budget easily doubles. Too much CYA, chlorine moves like it just ate two pounds of pasta fugeole. With the right amount, chef's kiss, simple. But holy hell did we manage to complicate it.

there is a pH fable you need to stop repeating. If you're repeating it.

It's like the horror franchise that just won't die. Let me say it clean. If CYA is in the pool, the old HOCL, OCL, that's hypochlorous acid, hypochlorite ion chart is garbage. It's useless. It's irrelevant. Unstabilized water? Sure. As pH rises, hypochlorous acid turns into hypochlorite ion. Stabilized water?

Nope, the second CYA shows up, chlorine binds to it, forms chlorinated isocyanurates. And once that bond happens, pH stops mattering the way you think it does. Chlorine does not collapse further at a pH of eight in a stabilized pool. This isn't my opinion. This is tested, measured, peer reviewed, CMAQ verified chemistry. Here's the thing, cyanuric acid,

plays such a role in weakening your chlorine right off the bat when you add it with a perfect pH.

that by the time it gets up to eight, it doesn't get much worse. But it starts out not good when you have cyanuric acid in the pool. I sat in the meetings, I've seen the data. So stop clutching to that old hypochlorous acid chart like it's gospel.

It belongs in a museum with dial-up internet and $36 trichlor tabs. Lab and modeling data presented to CMAX showed measurable disinfection even at cyanuric acid levels well above 90 parts per million, though with a little bit slower killing times. That's why the code still caps CYA often at 90 parts per million or less. Even though chlorine doesn't stop working at 100 plus, it does slow down a little bit.

Sure, but it keeps working, it keeps disinfecting. So does the deep end turn into a bacterial nightclub? Not necessarily. Why 90 parts per million? Well, this is the embarrassing part. Between test kit limitations and how often dilution tests get screwed up in real life, regulators landed on 90 parts per million as a practical ceiling. They may not say, don't trust operators in the code, but let's be honest, it's a big part of it.

The Taylor test, the most popular test people use for this, only reads up to 100 parts per million. If the dot disappears instantly, you know you're at least 100 parts per million or higher. How high? Who knows? That's where the dilution test comes in. But again, nobody trusts you to get it right. I'm not making that up. I trust you. I think you can do it. All it would involve is

if they want to really really make sure that it's easier is put another friggin line on that little squeeze bottle at a midpoint fill it up to here with bottled water fill it up to here with pooled water and fill it up the rest of the way with cyanuric acid test solution boom you have a 50 50 diluted test that's easy and simple that's not hard to that's that you won't that no one will screw up so

To find the real number, like I said, we got to dilute the sample bottled water works fine for that. And the number of techs who screw this up with a too much pool water, they say, not enough dilution water, tap water, bottled water, or my favorite, hey Rudy, I filled it halfway with bottled water. That's fine, right? No, no, it's not. Scientists basically threw up their hands and said, screw it. Let's cap it at 90 because we can't trust anybody to dilute anything. Insulting.

Yeah, accurate. I can't say no. I can tell you this. Nobody that I know in the industry would fuck this up. Nobody that listens to the Talking Pools podcast would screw it up. So, you know, other folks, the possibilities there, there's a potential. Now for the fun part, copper cyanide standing that blotchy blue purple nightmare nobody wants.

If you've been in the field long enough, you've absolutely walked into a backyard and seen plaster that was bluer than your balls on prom night. What's happening? Copper ions plus cyanurates equal a brilliantly purplish blue insoluble compound that adheres to the plaster like it's signing a lease. Sources? Could be failing heaters, ionizers, copper algaecides, old plumbing, you name it. Could come in your fill water.

And the homeowner special, I found this bottle in my garage. High CYA makes it worse, faster and more dramatic. You can't brush it off. can't shock it out. Running the pump 24 seven does diddly squat. Once copper cyanide forms, dude, that shit's committed. Like a tattoo you regret the next morning.

once CYA is in the water, pH still matters for a lot of reasons, but it no longer controls chlorine strength the way that old chart suggests. Okay, we spoke about that a minute ago. synergic acid in the free chlorine, synergic acid ratio becomes the main drivers of how active your hyperchlorous acid is.

the actual hypochlorous acid percentage at common CYA levels. For example, at 30 parts per million of cyanuric acid, 3 % of the chlorine is hypochlorous acid. At 50 parts per million, 2 % is hypochlorous acid. At 150 parts per million, 0.5 % is hypochlorous acid. This is the real world functional chlorine, and it helps explain why chlorine slows down, break point takes longer,

Ammonia even drags out and fecal incidents require insane CT values. It also hammers home the idea that cyanuric acid doesn't kill your chlorine, it just meters it out very slowly. Most techs don't understand one pound of trichlor adds

ten parts per million of free chlorine

Rudy Stankowitz AI (21:46)
6.

Rudy (21:46)
parts per million of cyanuric acid.

So you can add a very quick rant about how every time someone shocks with Trichlor a little voice in the universe cries and a pool pro dies. That's okay. Just like Tinkerbell, we can bring them back by clapping our hands. I believe, I believe, I believe this is one of the most practical field applicable.

pieces of cyanuric acid knowledge and you'd be surprised at how many pros don't know it.

You mentioned that it doesn't evaporate or go away on its own. Perfect. But you can add the only natural degradation pathway is

reducing bacteria. And it's extremely rare in chlorinated water. This shows that you're not just speaking from experience, you're giving the actual chemistry.

The part almost everyone gets wrong.

how your total alkalinity reading includes cyanurates. Remember? Carbonates, bicarbonates, hydroxide, and cyanurates. And that we need to account for the contribution of cyanuric acid to the total alkalinity for all of the time, not just for the saturation index. That's the number we should use all the time. So...

It's not just stealing from your total alkalinity. It's messing with your LSI behind your back. So how do we account for it? You subtract one third of your cyanuric acid from your total alkalinity and that gives you your adjusted or your carbonate alkalinity. That's the number we want to use for everything. Saturation index or whatever.

High cyanuric acid suppresses ORP readings because ORP sensors measure hypochlorous acid activity, not total chlorine. That explains why a pool sitting at 650 millivolts with a 30 part per million cyanuric acid level can drop to 500 millivolts at 90 parts per million cyanuric acid, even though the free chlorine didn't change. This one hits especially well with commercial

Rudy Stankowitz (23:44)
This is also the same reason why a pool that uses cyanuric acid, the operator or the pool person may see that the ORP is higher first thing in the morning and then gets lower as the day goes on. That's because hypochlorous acid has a stronger bond with cyanuric acid when subject to solar UV rays. So it attaches better. It holds on better.

But when it's dark out, it lets go. So more of your hypochlorous acid is available to oxidize in the water. And ORP is the oxidizing capacity of the water. So that's the reason why your ORP would be higher first thing in the morning

Rudy (26:30)
So I'm just going to say it boldly and

cut to the chase, no beating around the bush. There is no such thing as chlorine law.

It does not exist. What people call chlorine lock is excessive cyanuric acid with a large organic demand. Ammonia, very high bather load, biofilm, not some mystical locked chlorine. Adding this kills a myth that floats around like a turd in a lazy river. If your cyanuric acid level hits 300 parts per million, this is the holy shit section.

At a very high CYA level, CT values become

because they jump to not hours, but days. Breakpoint can require insane doses and water replacement becomes non-negotiable. You don't have to go deep. Just a quick, here's what happens when people go nuclear with stabilizer.

Yeah, Alan will lower it. I came up with that method. We tested it. It was proven in the beginning of 2024 in lab testing. So I'm happy about that. It was a tool that we developed for folks in drought areas where water use restrictions are in place. I still believe, and I always will believe that replacing water is the best

way to lower your cyanuric acid level. We didn't create it as a tool for everybody. If you're in an area with water restrictions and you can't drain and refill, that's what we came up with this for. If you're in an area with high groundwater,

So you can't drain it, you're worried it's gonna pop up out of the ground. That's what we developed this for.

You need the correct dose, correct pH, dead still water, perfect vacuum to waste

tech who doesn't measure things the same way they measure oregano for meatballs. When it works, it's beautiful. When it doesn't, you get a cloudy mess and a tech saying, so I followed something I found on the internet. Well, don't do that. Come on.

You all know how to get a hold of me. First off, the correct method has been printed in Service Industry News, Aqua Magazine, Cool Magazine. It's there. We've gone through it in the podcast before. We also have it on my site, CPOClass.com. If you want the instructions, go to the source. I created this process. The information is on my website, CPOClass.com. Go there.

I also have it on researchgate.net.

It's probably not the most academic thing I've written on researchgate.net, but I wanted to get the information out there. So just keep that in mind. Draining refill, still king. Fresh water fixes things immediately. No drama, no risks. When in doubt, drain it out. No praying to the pool gods. If it's safe to drain, do it.

CYA doesn't evaporate and it doesn't magically disappear. If draining isn't an option, okay, alum. But if draining is an option, do it every time.

I know sometimes we stand around and talk shit, but this time it's legitimate. We are literally going to be talking shit. So with no stabilizer in the water, we know chlorine nukes pathogens fast. With stabilizer, nope, everything slows down. That's why the CDC requires higher chlorine, longer times, no shortcuts. Commercial pools avoid cyanuric acid for a reason. It isn't evil, but pathogen kill times matter.

So here's the deal, normal fecal incident, we're not worried about it. Floater, right? Solid stool. Two parts per million, 25 minutes, a pH of 7.5 or less. That's what we shoot for in the chemical treatment there.

Diarrhea incident. Okay, the whole process there. Obviously we shut down the pool, get people out of the water. Don't leave them milling about on the pool deck because if you leave them milling about in the pool area, they're going to try to get back in. I've had people come up to me and say, ⁓ look, they had diarrhea on that side. Can I swim over there? No. So lock the gates, them on the outside of it so they're not in the pool area. Next step, you gotta scoop.

the poop. You got to get what you can. You got to chase the chunks, chunk the corn, don't care what you call it, but you got to scoop out what you can. And then you dispose of it in a means in accordance with your local sanitation department. Most likely they're going to tell you to double bag it and throw it in the dumpster. Or guess what? It's poop. They might just say flush it. So that's an option. Now

I throw my poop scooping equipment into the pool. My poop scooping equipment has to go through the same process that the water goes through in order to sanitize it properly so that way I don't recontaminate the pool next time I go to scoop something out. I'm going to raise my chlorine level now up to 20 parts per million. 20 parts per million. That means you cannot use your test kit to confirm this.

because we know using the reagents, the drop test, five drops of DPD-1, five drops of DPD-2, what's gonna happen at a chlorine level over 10, you're see a flash of pink and then it turns completely clear.

We could do a dilution test, but it's better to do a test that can give you a more accurate reading without anybody guessing or questioning your ability to do a dilution test. So that's why the FASDPD method of testing chlorine.

is the better test to run when we're trying to confirm a level of 20 parts per million. If you're using the drop test, you're just guessing. If it's a dilution test, they're going to say it was sloppy. Get this test kit so you can say, used this. So that way there's no question.

photometers, they will give you numbers over 10 parts per million. They will, but according to the manufacturer, those numbers are inaccurate. The only numbers that are accurate that they can tell you that they guarantee are those numbers between one and 10. Anything above 10? You can't rely on that. So get the FAS DPD method of testing chlorine. It's the one that uses the powder. It's a titration test. The titration test is where we count drops to make a color change.

as opposed to matching colors, which is known as colorimetric, when you hold the test block up and match color by eye. Okay, so 20 parts per million, we're gonna hold it there for 12.75 hours with a pH at 7.5 or less. Again, pH at 7.5 or less because of chlorine's effectiveness being pH dependent.

The lower the pH, the more effective the chlorine is. So at 7.5, your chlorine is 50 % effective. At 7.2, it's 66 % effective. at 7.5 or less, essentially what we're saying is we want the chlorine to be 50 % effective or better. Okay, 12.75 hours pass.

We're almost ready to let people in. It was diarrhea. We scooped out what we could. We couldn't get it all. It must've went somewhere. Now it's time to backwash or clean your filters to waste. Once we've done that, we have this high chlorine level. We were up at 20 parts per million. We need to bring it down to at least 10 parts per million in most areas. Indoor pools, five parts per million. Some areas it's gonna be as low as four parts per million. So check your code before we decide to open the pool back up to bathers.

that's the process for treating a diarrhea incident.

in a pool that does not use cyanuric acid. And that might not be the way you learned it, but that's the way it is now since 2017. So I mean, if you've been in the industry for a long time and you've looked at the fecal incident response procedures in the past decades ago, there's always been a footnote at the bottom of the page that stated specifically

unable to obtain a 99.9 % kill rate of Cryptosporidium in the presence of cyanuric acid. Always a footnote on those sheets. So in 2017, they decided that they'd actually address it and create a whole separate process.

Why does it matter? Well, if your health department code references the CDC's fecal incident response procedure for you for treating fecal incidents in pools, well guess what? That makes this the law. And you could be held accountable if you have acid and somebody gets sick. So here's what we do in a pool with a cyanuric acid level. Much the same.

We close the pool, we get the people out of the water, we scoop the poop, we dispose of the poop, we throw the poop scooping equipment into the pool. Now we're ready to start treating it chemically. The very first thing that you need to do is lower your cyanuric acid level to 15, that's one, five, 15 parts per million or less. We just discussed how we lower cyanuric acid, so we're gonna have to replace water.

If your cyanuric acid level is at 30 and we need to drop it to 15, that means you're draining and refilling half the pool. Do make sure that you hose down those walls thoroughly as it's draining because sometimes cyanuric acid likes to stick to plaster and when you refill it, the level might be higher than you wanted it to be. So.

hose the walls down as you're draining and refilling. But you're wanna replace half the water to get to 15. If you're at a number higher than that, well guess what? You're replacing more than half the water before you can begin. Here's the other thing. Most of us use that visual determination test, make the dot disappear test for cyanuric acid in that Taylor test kit.

if we're using that, think about it. Look at your test block if you have it in front of you. The lowest number that gives you is 30 parts per million.

The lowest that method of testing can detect is 20 parts per million. So we can't use that test block for this.

you're going to need a photometer to test levels that low. Again, otherwise you're guessing. Now, once we get the cyanuric acid level to 15 parts per million or less, we're going to again raise the chlorine level up to 20 parts per million.

We're going to confirm it with our FASDPD method of testing chlorine. We are now going to hold it there for 28 hours.

with a pH of 7.5 or less. And again, of course, the chemical we use to test pH is phenyl red. That works really good for us with pH because phenyl red has the ability to test a pH from 6.8 to 8.4. Our acceptable range we shoot for 7.2 to 7.8, so it just fits in there nicely and bookends it But.

should you try to test your pH when you have the chlorine level up that high, you're going to get a very dark blue result because at a chlorine level of 15 parts per million or higher,

Chloride actually bonds with phenyl red and what you get is a new chemical known as chlorophenyl red. Chlorophenyl red can still test pH. It's still used in science to test pH except it tests a very different range. Chlorophenyl red can only test a range between.

4.8 and 6.6. So anything greater than 6.6 on the pH scale, that's everything in your acceptable range, is going to come out that dark, deep, purplish blue color.

So once we've held it for 28 hours, okay, again, now we go back and again, 28 hours. That's even if you only have one part per million of cyanuric acid in the water.

Don't half ass it. Make sure you document it. Make sure you do it the right way because you know what? God forbid somebody still gets sick even after you did it correctly. When you go into court to talk about this, show them the documentation you want to be able to say without a doubt, here you go, look, this is what I did. This perfectly matches what the health department wants us to do. And we follow the CDC's fecal incident response guidelines to a T. I'm sorry that person still got sick, but we did everything correctly.

So make sure you document it and do make sure that you have the tools necessary to do this correctly.

So yeah, so now we clean the filters to waste. We drop our chlorine level back down to whatever the acceptable limit is for the state and open up the pool. Everybody can get back in except for the little bastard that shit in the pool. That kid should be punished.

So we were speaking before about the secret threat where cyanuric acid adds to total alkalinity. And unfortunately, this is something that too many techs ignore. Cyanuric acid contributes roughly a third its value to total alkalinity, like I said a moment ago. So 90 parts per million cyanuric acid, that's about 30 parts per million total alkalinity added. If you ignore that

and suddenly your LSI is corrosive, your heater is dissolving, and the copper levels are skyrocketing, and you're unaware because you think, hey, that's weird.

because my LSI was in balance. Well, if you didn't take into consideration the contribution from cyanuric acid, no, your LSI was not in balance.

Jumping back to the alum thing. I know some of you wanna know, so I'm gonna go through it with you really quick. To lower cyanuric acid with alum, there's a lot of particular steps here, but it does work and it works every time as long as you follow the steps. And what you should expect, at least from what we've seen in the field is anywhere from a 30 to 50 % reduction in the cyanuric acid level in the pool. So step one, we want a pH of 7.0.

I know a lot of people say, ⁓ you need a higher pH when you flock. Well, they say that because alum is acidic and it will bring the pH down and they're hoping after you flock that it's still in range. It doesn't mean it works better there. The truth is that alum will actually flock between 4.4 and 9.5. The difference is at the higher pH, it's going to take more product.

and it takes a longer time to flock. So 7.0, if I could go lower and not worry about somebody destroying a pool, I would, but let's just call it seven. We ran all of our trials at seven. So it's a working number that your test kit can detect easily. So 7.0,

Total alkalinity in the ideal range, somewhere between 80 and 100 parts per million. We'll call it 90, that works fine. We need a temperature, a water temperature, 70 degrees Fahrenheit or better. It has to be higher than 70 degrees Fahrenheit.

Rudy Stankowitz (41:00)
That's 21.11

Rudy (41:04)
With the pump running, we're going to broadcast evenly across the pool surface aluminum sulfate at a rate of 8.33 pounds per 10,000 gallons.

Rudy Stankowitz (41:15)
That's 3.78 kilograms per 37,854

Rudy (41:23)
I know the normal dose is four to six pounds per 10,000 gallons. It's not enough.

to do what we're looking to do here. That's a great amount. If you need to actually flock the pool, you have a green to clean, four to six pounds per 10,000 gallons, awesome. If you need to take out staining, four to six pounds per 10,000 gallons, awesome. But here to drop cyanuric acid, 8.33 pounds per 10,000 gallons.

Rudy Stankowitz (41:48)
That's 3.78 kilograms per 37,854

Rudy (41:56)
That is the exact same dose that your municipality uses.

to get all the schmutz out of the water when it first pulls it in from the reservoir. So we're going with the same number that drinking water facilities use. 8.33 pounds per 10,000 gallons across the pool surface evenly with the pump running. We allow the pump to run for two hours and then shut off.

you do wanna bypass the filter. If it's a sand filter or a DE filter, just put the valve in to recirculate. Of course, we do that with the pump off. We don't move a valve handle with the pump running. We don't wanna risk water hammer. So, or if it's a cartridge filter, we just take it apart, take the element out and reassemble it without the element inside. Again, then we run it two hours.

so it can circulate a bit through the water. Pump shuts off. We come back the next morning at least 12 hours later. If you wait longer, that's fine. Just make sure that the pump didn't come back on. We don't want anything to stir up the flock that we've created.

than a slow vac to waste. Yeah, you're gonna end up having to replace some water. What we're looking at is probably a couple of three inches in a slow vac to waste in a pool, depending on how well you slow vac to waste. You're not gonna wanna use your customer's equipment. A port of vac works best.

If you're going to do this, and you're going to do it often, I would invest in one just for using alum in general, even at the other dose and for the other reasons. This will also remove the phosphates from the water, this dose. So not only are you taking cyanuric acid out, you're also lowering the phosphate level and probably bringing down your TDS a little bit as well.

Slow vac to waste. Here's the thing. People have come back at me and said, you're adding aluminum to water. You're adding metals to water. Well, if you do the slow vac to waste correctly, when you vacuum out the flock, you'll be removing all the aluminum you put in. We've tested it afterwards repeatedly. Now I will tell you the EPA for drinking water has a 0.2 part per million level.

for aluminum, allowable level for aluminum, but that's not something that's monitored.

It's a secondary.

It's considered a

Rudy Stankowitz AI (44:16)
contaminant.

Rudy (44:17)
we've tested it and we've been far below that. We've been at zero most of the time, sometimes 0.1, but still far below the 0.2 parts per million that the EPA gives us they don't regulate it. They don't even look at it. And the only reason they recommend that it stays below 0.2 is for odor and color, not for danger.

just for odor and color. So stop stressing it, right? And we're vacuuming it out anyway.

anyway, cyanuric acid, most of your chlorine bonds to it, a tiny percentage stays free as hypochlorous acid. That's the stuff doing the sanitation. Chlorine gets used more releases from that reservoir. That's why stabilized pools lose chlorine slowly, but they also recover slowly. Cyanuric acid doesn't kill chlorine. It just puts it in slow motion.

Rudy Stankowitz (45:01)
I will say this, and this isn't something that's widely known, but when you have a cyanuric

Rudy Stankowitz (45:06)
level and your pH gets higher, a lot of changes go on. hypochlorous acid is the form of chlorine that attaches to cyanuric acid when exposed to UV rays, We got that. But as the pH increases, we get more hypochlorite ion, which is weaker I mean, it still does sanitize. It's just not as effective as the hypochlorous acid.

But, hypochlorite ion does not have the same attraction to cyanuric acid that hypochlorous acid does. So as the pH goes up, more hypochlorite ion, less hypochlorous acid, the hypochlorite ion peels away from the cyanuric acid, and guess what? It's It's subject to solar UV degradation, and you go through greater amounts of chlorine.

Rudy Stankowitz (45:58)
I know I didn't really talk much about cyanuric acid as a buffer against the downward drift in pH. And I know it's recommended for that a lot. It's part of the three things folks recommend as far as buffers go, Total alkalinity between 80 and 100 parts per million, cyanuric acid at 30 parts per million, and a borate level of 50 parts per million. But the reason I didn't get too in-depth into it earlier, and we'll talk about it a little bit now, is because cyanuric acid

actually sucks as a buffer. mean, chemically, yeah, it can, but the effect in pool water is really, really small. Syneric acid is a weak polyproduct acid with a pKa near 6.8, which means on a molecular level, yeah, it has the ability to release or accept hydrogen ions, which is the definition of a buffer So when the pH begins to drop,

extra hydrogen ions appear in the water, cyanuric acid can actually grab up some of those hydrogen ions, converting into a more protonated form of itself. That reaction removes a small amount of acidity from the water and yeah, slows the downward drift in pH. So in chemistry terms, I mean, that's how that works. But here's the important part. Even though the chemistry allows CYA to buffer, its real world influence in pool water

It's minuscule. It's tiny. At normal pool pH, 7.2 to 7.8, almost all cyanuric acid is already in its fully protonated form. Only about 1 to 3 % exists in the conjugate base form. that's needed for meaningful buffering. A buffer only works when the acid and the conjugate base are both.

present and in similar amounts. Remember when we were talking about total alkalinity and we talked about borates and how they had a perfect pH, where you have just as much of the conjugate base as you do of the weak acid. It's just not here for cyanuric acid. So yeah, technically it resists

a pH drop, but the actual buffering capacity is extremely limited, alkalinity, which does almost all the heavy lifting in a pool. I mean, picture it like this. CYA is like one person trying to slow down a rolling car. Technically, they're pushing it in the right direction, but the car barely notices.

Bicarbonate alkalinity on the other hand is the entire breaking system and it does almost all the real work of stopping the pH from crashing. So does CYA buffer against the downward drift in pH? Yeah, chemically. But in a swimming pool, the buffering strength is really, really weak and the practical impact is minimal. Bicarbonate alkalinity is the primary pH buffer that you rely on and that's the chemistry of it.

clear, accurate, grounded, and real-world pooled behavior, which is where it really matters.

Rudy (49:04)
here's the deal. Cyanuric acid, it isn't good or bad.

just needs to be understood. Keep it between 30 to 50 parts per million. Keep it under 90 parts per million. Know how to test it and know when you need a dilution test. Understand what it does to total alkalinity, LSI, pH and kill times because cyanuric acid isn't the danger. The danger is the tech who refuses to learn it. That's all I have for you for this week. I know it was a lot.

Hopefully I didn't soapbox too much in there. If you have any questions, hit us up, talkingpools at gmail.com. If you liked the episode, give it some love. Five star review.

Nice words, always much appreciated. Everything helps. I'm Rudy Stankiewicz. This is the Talking Pools podcast. Until next time, be good, be safe.