After a brief overview explanation of Cyanuric Acid, we discuss what raises and lowers CYA. In short, it won't rise naturally, and to lower it, you need to dilute water.
00:00 - Introduction
00:54 - What is Cyanuric Acid (CYA)?
03:33 - CYA controls the speed of chlorine
05:04 - Minimal CYA is our Fourth Pillar of proactive pool care
06:25 - What raises CYA?
08:18 - What lowers CYA?
11:05 - Summary. Thanks for listening!
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94. 4/7 - What raises and lowers Cyanuric Acid (CYA)?
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[00:00:00] Eric Knight: Welcome back and thank you for being here as we continue our journey, learning what raises and lowers specific chemistries in a swimming pool. This is episode 94, which is four out of seven in our seven part series. In the past three weeks, we talked about pH, alkalinity, and calcium. And in this week's episode we are going to talk about what raises and lowers cyanuric acid.
[00:00:23] Now, we cover CYA in more depth in a lot of episodes. Ready for this? Episodes 8, 20, 24, 29, 36, 47, 59, 70 and 79. Yeah, it's pretty important because cyanuric acid interacts with a lot, both on the sanitation side of water chemistry and on the balance side. So let's get right into it. Episode 94, Let's go.
What is Cyanuric Acid (CYA)?
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[00:00:54] Eric Knight: How about we start with a brief overview of what cyanuric acid or CYA is? CYA is also known as stabilizer or conditioner. It's the same stuff. What it does is it protects free chlorine from breakdown from direct sunlight. Specifically the UV light. It's kind of like an umbrella or sunscreen for chlorine. And that's a really big benefit because if you didn't have cyanuric acid in an outdoor pool, free chlorine has a halflife of about 45 minutes, which means in 45 minutes you will lose half of your chlorine just to sunlight.
[00:01:52] A little bit of cyanuric acid makes a tremendous difference in how long you can hold chlorine. But too much of a good thing becomes a really bad thing. One of the biggest problems we see in swimming pool chemistry is overstabilization.
[00:02:05] That's because cyanuric acid impacts both sides of water chemistry, balance and sanitization. On the sanitization side, or disinfection side, CYA, yes, it protects chlorine, but it also slows it down. So a little bit is a really good thing. But if you have over stabilization, your contact times for killing given pathogens goes way up. Contact time, meaning the amount of time it takes chlorine to kill something. So if you have a CT value of 10, one part per million takes 10 seconds to kill that germ. Or 10 parts per million of chlorine takes one second to kill that germ.
[00:02:43] Well, if you introduce cyanuric acid to that, those CT values change. They get much longer. So just be aware of that. Too much CYA really slows down your chlorine.
[00:02:54] Cyanuric acid also contributes to your total alkalinity in a small way. We discussed this two episodes ago. Approximately one third of your CYA is cyanurate alkalinity, and that has to be deducted from your total alkalinity to figure out your corrected or carbonate alkalinity when doing the LSI.
[00:03:12] Don't worry about that because our calculator factors all this in for you. Just be aware that the more CYA you have, the more aggressive your LSI is. So when you raise your CYA on the calculator, you'll notice the LSI goes down. That's because it is increasing the amount that you have to deduct from your total alkalinity.
CYA controls the speed (strength) of chlorine
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[00:03:33] Eric Knight: Another key thing to know about CYA is if you have any of it in your water, the pH no longer controls the strength of your chlorine. Or it's in a very negligible way. Because when we think of chlorine strength, we're talking about the percentage of HOCl, the percentage of hypochlorous acid. And if you have CYA in your water, that percentage is like 3% or less. As opposed to a pool that had no CYA in it, where at 7.5 pH, it's like 50/50 between HOCl and the hypochlorite ion, OCl-.
[00:04:09] If you have a lower pH without CYA, your chlorine strength is way stronger. That's why it's more efficient to have a lower pH on, say, an indoor pool. But with CYA, you still have chlorine, you'll still test for it, but it's bound to cyanuric acid, so the chemistry is different and is not nearly as pH dependent.
[00:04:30] So just be aware you could have roughly the same speed of chlorine at 7.0 that you do at 8.0 pH. This is important because we have been chasing pH for so long in this industry, because the textbooks told us to. But in reality, if you have any CYA in your water, you probably don't have to do that for the sake of chlorine's strength.
[00:04:51] Now, you do need to manage pH for LSI reasons, and we discussed that in episode 91 and many other episodes as well. But it's not for chlorine's strength. All right, so keep that in mind.
Our Fourth Pillar of Proactive Pool Care
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[00:05:04] Eric Knight: Now if you haven't had a chance to take our Four Pillars program, we have an academy program called Four Pillars. We also have several blogs about them. Our fourth pillar of Proactive pool care is called Minimal CYA. That's pretty self-explanatory. It is essential, in our mind, that you do not let over stabilization occur.
[00:05:27] Now we say you should stay below 50 parts per million on a residential pool and 30 or less on a commercial pool. But it doesn't have to necessarily be that exact number. We just use it as rule of thumb because it really matters the ratio of your free chlorine to your cyanuric acid. But in most cases, stay below 50.
[00:05:48] Don't worry about the science, just stay below 50. On commercial pools, the CDC actually recommends no more than 15 parts per million because of CYA's why's dramatic impact on the contact times required to kill recreational water illnesses. Specifically Cryptosporidium. If there was a crypto outbreak in that pool, how long would it take to kill it? Well, the contact times with CYA just get immeasurably long. We're talking days and days, if not weeks. Crazy stuff. You should look into that on your own. I'm not going to discuss it here. Just know that you want some, but you don't want a lot.
What raises CYA?
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[00:06:25] Eric Knight: Now, let's get into this. What causes CYA to increase? There are only two ways you're going to increase cyanuric acid, and that is going to be either stabilized chlorine or putting a cyanuric acid product in your pool.
[00:06:40] The stabilized chlorine are trichlor, like those three inch tabs or sticks, and dichlor. Usually a granular shock. Trichlor and dichlor are about 50 to 55% cyanuric acid by weight, and one pound of trichlor in 10,000 gallons is going to raise your CYA about 6 to 6.5 parts per million depending on the purity.
[00:07:03] So let's just call it six for easy math. That means each tab in 10,000 gallons is about three parts per million CYA. It adds up quickly if you're using trichlor as your primary chlorine. Dichlor shock is not used nearly as commonly, but it'll do a similar percentage.
[00:07:21] Now, cyanuric acid products would be granular CYA, which is most common in commercial pools, and you could buy it from any pool distributor, you can buy it online. But there's also liquid CYA. Liquid CYA is another product you can get at the pool store. So both of those will raise your CYA. Try to keep it below 50 residential pool owners. Residential pool service pros. Stay below 50. That's not a problem if you're putting in liquid CYA or granular because you just don't add more.
[00:07:51] But if you are continuing to use trichlor, that's where over stabilization becomes a problem. Because the CYA just keeps accumulating. Stay on top of it. You don't get any sunlight benefit the higher you go past, I think it's 70 parts per million. You already have a hundred percent of the protection. All you're doing now is complicating your chemistry and slowing down chlorine. So keep your CYA to a minimum.
What lowers CYA?
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[00:08:18] Eric Knight: Now what causes CYA to decrease? Boy, this is one of the most common questions we ever get because high CYA is a problem and people know it, and a lot of people call our hotline and reach out through our help center, ask dore ask.orendatech.com, How can I lower my CYA?
[00:08:35] Boy, that would be the holy Grail in the swimming pool industry. If there were a way to get CYA out effectively, like with an enzyme or something. As of now, the technology is progressing that way, but it doesn't exist yet. This is the year 2022. Hopefully I'm wrong in the next few years. That would be wonderful.
[00:08:54] Uh, trust me, if we knew of a way to chemically remove CYA safely that could be NSF-50 certified, we would have it. The main way to reduce CYA is dilution. You need to get it out of your pool. You need to lose whole water. Now, that could be extended backwash cycles that could be draining, just like you're trying to reduce calcium hardness in the last episode. Getting physical water out of your pool and replenishing it with tap water that does not contain CYA. Rain and snow dilution also help because they also do not contain CYA. So that helps.
[00:09:31] But it could also be a pool leak. Not that you want to have a leak, I'm just saying if your CYA is going down, down, down and you're not trying to make it go down, you could have a leak. That's one of those signs that could say, Oh wait, my calcium, my CYA, my TDS, they're all dropping and I'm not doing anything. You might have a leak. That should be something that triggers you to do a leak detection.
[00:09:53] So anyways, dilution is the best solution today. There is another product out there that is a nitrifying bacteria. Mixed results on that. Um, theoretically it works well, but essentially a nitrifying bacteria requires dechlorination of your pool, and then this bacteria will convert cyanuric acid into uric acid, which eventually, I'm, I'm paraphrasing here. Eventually it breaks down into urea and ammonia, and then chlorine can go through the breakpoint chlorination process and process that ammonia out. It takes a lot of chlorine, a lot of time, and you have to de chlorinate first. So it's not very practical. But if you can't drain your pool, it might be your only option.
[00:10:37] Now, I hope in the next few years, because this is such a major problem in swimming pools, that new technology will arise that reduces CYA more effectively than just draining and diluting. But you've got entire teams of huge chemical companies with very smart people that have been working on this for years, and they haven't figured it out yet.
[00:10:59] So I don't know. I don't know what's going to happen with it, but for now, dilution is the best solution.
Summary
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[00:11:05] Eric Knight: So to recap, if you want to increase your cyanuric acid, you have to put it in the water, either through stabilized chlorine or through a CYA product. And if you want to remove it from water, you have to remove water. This has been episode 94 of The Rule Your Pool podcast, part four of seven, and we hope to see you in the next three. I'm your host, Eric Knight.
[00:11:27] Thank you so much for listening. If you have questions, the email is podcast@orendatech.com. You can also check out our help Center of Frequently asked questions, ask.orendatech.com. Thanks for listening.