Bob Lowry: Party-Ready Pools and Alkalinity Control

Big bather load on the calendar and worried about cloudy water, itchy eyes, or a long recovery the next day? We brought in legendary chemist and educator Bob Lowry to map out a clean, simple plan that keeps your water clear and your sanity intact. 

We start with the pre-party checklist: raise free chlorine a few ppm, add a measured dose of non-chlorine oxidizer, and keep the pump and filter running. Then comes the sleeper tactic that saves the most money and headache—pre-swim rinsing. Bob explains why sunscreen, deodorant, and lotions burn through sanitizer in the first minutes and how a quick rinse slashes chloramines, improves smell, and protects comfort. 

The conversation then zooms into chemistry that often gets overlooked: cyanuric acid’s hidden impact on water balance. If trichlor is your workhorse, CYA climbs steadily, and your required free chlorine must climb with it—about 7.5 percent of CYA when you’re not using borates. Bob breaks down adjusted alkalinity (carbonate alkalinity), why you subtract about one-third of CYA from total alkalinity, and how a pool can be corrosive even when TA looks “perfect.” If CYA is sky-high, partial drain and refill beats chasing pH and TA forever.

Finally, we tackle a scary test result—pH near 5—and show the controlled fix: use soda ash to nudge pH, baking soda to build alkalinity, and aeration to finish the pH rise without clouding the pool or overshooting. 

• Raising free chlorine and using non-chlorine oxidizer before guests arrive
• Keeping the pump and filter running during and after a party
• Why pre-swim rinsing slashes chloramine formation and chemical costs
• How trichlor drives cyanuric acid growth and chlorine demand
• Using 7.5% of CYA as the free chlorine target without borates
• Adjusted (carbonate) alkalinity and its impact on the saturation index
• Corrosion risks when CYA is high and TA looks “normal”
• Draining to reset CYA to a manageable range
• Lifting very low pH with soda ash, then building TA with baking soda
• Finishing pH rise with aeration t

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Chapters

• 0:00 Welcome And Episode Setup
• 2:40 Bob Lowry’s Background
• 4:21 What If: Pool Party Scenario
• 5:19 Chlorine Boost And Oxidizer
• 6:07 The Power Of Pre‑Swim Rinsing
• 8:41 Keep The Pump And Filter Running
• 10:10 Cyanuric Acid And Adjusted Alkalinity
• 13:19 Managing High CYA And Chlorine Ratios
• 16:19 Carbonate Alkalinity And Corrosion Risk
• 19:18 Draining To Reset CYA
• 19:56 Raising Very Low pH Safely
• 21:38 Soda Ash Vs Baking Soda Strategy

Transcript

SPEAKER_02: 1:02

Hey, welcome to the Pool Guy Podcast Show. Bob Lowry shared a lot of knowledge in the podcast that I did with him back in 2000, 2021. And I think this one here is something that you're going to learn a lot from. This is about pool party prep, what you do before you your customer has a pool party. And also we talk about adjusted alkalinity, the best way to fix alkalinity that's really out of balance with the pool chemistry. Are you a pool 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 swimming poollearning.com. So I'm joined today by Bob Lowry, and I'll let him introduce himself and give you just a little bit of background. He's been in the industry pretty much since it started, right? Since the pool industry started.

SPEAKER_00: 2:02

Well, um, I got in the industry in 1973. Uh in and so I've been in the industry for 48 years, but I'm 75 years old, so I wasn't a kid when I got in the industry. I was I was a grown guy. At any rate, uh I guess I was 20-something when I got in. But anyway, I've been in this industry for 48 years, and I've owned two chemical companies and a publishing company that would be Robarb and Leisure Time Chemical. I've also owned Service Industry News. And I was the technical director at Leslie's for five years, was also in charge of their uh new product development and their formulation department and their safety department, which we which was company wide, making sure that the store was complying and and keeping all of their uh employees safe. Um so we we made videos and books and things like that. In any case, since then I uh became a consultant, and I've been a private independent chemist consultant for about 25 years now, and uh actually 26 years. So um I'm independent, I don't have anything to sell but books or courses and information.

SPEAKER_02: 3:29

The listeners appreciate all the knowledge you share. And so in this series, Marvel has a a new series on Disney Plus called What If. So I thought we would do some what if questions here. Nothing weird, but just some pool what if questions. Some of these I've gotten from people, and I figured you would be the one that would be able to answer these. So let's start with the first one. Let's say the softball team calls you and 15 players are coming over to go swimming. What is the first thing you would do?

SPEAKER_00: 3:58

Well, I would probably suggest that you raise the chlorine level up, probably by whatever's in there now. I would probably add four or five parts per million more of chlorine. I would perhaps add a non-chlorine oxidizer like monopursulfate, um, and just add whatever they suggest as a shock, because you can go in the water with a uh with the recommended oxidizer amount, you can go in the water right away. So raise the chlorine level, add the non-chlorine shock. The biggest thing that you could do is see if you could get them to rinse off before they get in the pool. And the reason is that that, in fact, you can save money at any pool if you can get the bathers or people that are getting in the pool, if you can get them to rinse off before they get in. Because the biggest consumption of chlorine is from people. And well, not exactly, but over a week's period, the biggest loss of chlorine is to sunlight, because you lose about a part per million per day of chlorine to sunlight. But when people get in the pool, it disappears pretty quick. So, in a busy pool, the biggest use of chlorine is some people. The stuff that's in our bodies, on our bodies, comes off as soon as we get into the pool. So the biggest use of chlorine is like the first 15 miniature in the water. After that, there's not much new contamination getting in there. The initial insult of you getting into the pool uh is where everything uh uses up the chlorine. You've got on sunblock, deodorant, maybe some hairspray, uh some lip balm, uh foot powder, you know, you got gels and creams and stuff like that, and and all of that stuff is on your body, and it's not in your body. And as soon as you get in the water, most of it comes off. And so chlorine, it needs to be oxidized. And either chlorine has to do it or non-chlorine shock has to do it. So if you can get people to rinse before they get in, you can save big money on chlorine and oxidizer. And they did a study in England right around 2000. It proved that they could save 60% of the chemicals by people simply rinsing off before they get in. And it became so huge, the report became so well known that they actually made it a rule. When you get in a public pool in the in England, you have to rinse off before you get in. And so it's a rule. Um, anyway, between those three things, uh, you can manage it. Raise the chlorine level, add a non-chlorine shock, and and ask the guys to rinse off before they get in. And it won't be a difficult problem then. If you do nothing, you're gonna play catch-up. And once the chlorine starts forming chloramines with all of those things that are on all those soccer guys, you know, then it takes even more chlorine to get rid of it. It's a big savings if you can get them to rinse and have some chlorine in the water when they get in, and it'll oxidize that stuff right away.

SPEAKER_02: 7:33

And if they're looking for non-chlorine shock, Leslie's pool suppliers carries it. And then your main suppliers carry it. I think the main brand that Pool Corp supplies is called Shock Treen. Um, so that's the non-chlorine shock if anyone's looking for that for their pool route or for their pool. So, like you said, that's a great way to kind of hedge that. And another, I guess the second part of that question is a lot of pool owners like to turn their pool off while people are using it for a lot of reasons. Maybe their automatic cleaner is working in there, or they have a water feature that's making noise, or just the equipment by the pool is making a lot of noise. You don't advise that if you have that many people in the pool, right? You want that filter running.

SPEAKER_00: 8:29

No, you need that filter gone. You need the filter going. And and the great thing is that that the chlorine that's in the water then doesn't have to work on the stuff that's in the water because the it's trapped in the filter. So the chlorine then that's in the pool is free to kill the stuff that's in the pool. So it's really important that you keep that that that pump and filter on for a long time. And and particularly after a big bather load gets out of your pool, you need to leave the filter on for at least a turnover.

SPEAKER_02: 9:08

Another question here that I get often, uh, and it this happens a lot, where the cyaneric acid is 200, they're testing it, they do dilution tests, and it comes in at about 200, but the alkalinity is at 70 or 80. So, how would you do an adjusted alkalinity on a pool with such a high cyanaric acid reading and such a low alkalinity reading? Because I think those can't go hand in hand when you use a lot of tablets, the alkalinity stays pretty low.

SPEAKER_00: 9:31

Yeah, well, it stays low because uh the tablets actually have a pH of about 2.8. So when you when they're added to the water, even though they're dissolving slowly, you're still adding that acid. And that acid will take away the pH and the alkalinity. But then with aeration and all the other things going on in the pool, the pH may go up, but the the alkalinity goes down. So you can have a problem with that. Or if you're using a lot of trichlor, then the pH and alkalinity both go down. You get cyanuric acid buildup. And the buildup is that for each 10 parts per million of chlorine that are added to the water by trichlor, you get six parts per million of cyanuric acid. And that can be in a pool if the main source of chlorine is uh trichlor, then the the use of chlorine in a pool is about one part per million per day from sunlight and just regular degradation. Then if you add bathers to that a couple of times a week, you're looking at about 10 parts per million per week of chlorine use. If it's all coming from dry chlorine, that means your cyanuric acid's gone up by six parts per million per week or twenty five parts per million per month. And that is big because uh we say that you need you need a chlorine residual that's in the pool that's equal to a percentage of the cyanuric acid. And if you're not using borate in your pool, then the the cyanuric acid, the free chlorine level should be 7.5% of cyanuric acid. If the cyanuric acid level is going up by 25 parts per million per month, that means that next month you need 1.5 parts per million of chlorine more residual in the pool than you use this month. And the next month, 1.5 parts per million more of that. And so each month you have to keep increasing the chlorine level by 1.5 parts per million. If you don't do that, then you can have algae start to grow. And then you got a shock and add algae and all kinds of stuff trying to get rid of the algae. So if you keep the chlorine level up, you won't have the algae. But the higher the cyanuric acid level, the higher the free chlorine residual needs to be. And so it's better to reduce the cyanuric acid level and then use a percentage of it uh as a residual. And the problem with a cyanuric acid level that's very high is that when we calculate the saturation index, which is an indication of whether the water in the pool is corrosive or uh scale forming. When we check the cyan the saturation index, we may find that the that with the adjustment for cyanuric acid, that the water is actually corrosive when we didn't think it was. And the adjustment is that about one-third of the cyanuric acid reading needs to be subtracted from the apparent total alkalinity reading. And so you get an adjusted alkalinity reading, and the adjusted alkalinity reading is actually called carbonate alkalinity instead of total alkalinity. It's called carbonate alkalinity, and we use carbonate alkalinity in the calculation of the saturation index. You can see if you actually had a cyanuric acid level of 200. If you take one-third of 200, you're looking at what is that, 68 or 67? You're taking 67 away from whatever your total alkalinity reading is, and if you got 70 alkalinity, you basically have zero carbonate alkalinity in the pool. And that that's got to mean that you have corrosive water.

SPEAKER_02: 14:03

And that would cause staining in the plaster in a lot of cases. I've seen that staining.

SPEAKER_00: 14:17

Which then, when the metal builds up in the pool, it surpasses the saturation point, and then you get a stain.

SPEAKER_02: 14:27

And I wonder, Bob, if you know some people were saying the cyaneric acid is damaging to the plaster, but it's not the cyanic acid itself. It's probably the fact that the alkalinity is so low. The carbonate alkalinity.

SPEAKER_00: 14:39

Right. You end up with corrosive water. Uh you get a you get the water into a corrosive situation, and you don't think you are, because you may be keeping the alkalinity at at say a hundred, which if you look at the at the guidelines from PHTA, it says it should be between 80 and 100. So if you look at, I mean 80 and 120. So if you had 100's right at the middle. So if you look at it and say 100's great, but if you had total alkalinity, I mean uh cyanuric acid of 200 and you subtract 67 from 100, now your carbonate alkalinity is only 33. You're looking at a carbonate alkalinity of 33, and that's not good. And you don't even need the saturation index index to figure that out. Nobody would tell you that an alkalinity of 30 is okay. And the problem is if you raise your alkalinity to compensate for high cyanuric acid, then the pH keeps going up because high alkalinity pulls the pH up. So if you run your pool at, say, 140 of alkalinity, it's going to keep pulling the pH up all the time. And you're going to have to deal with a high pH. And if you try to lower the pH with acid, it lowers alkalinity. So it's just as a game of chasing it around. So you're a lot better off, obviously, to drain the pool to get the cyanuric acid level down to 50 or 60 to parts per million so you can deal with this.

SPEAKER_02: 16:21

Now here's another one that happens. This is mainly for those large vinyl pools back on the East Coast. What if your pH is five and you have a 25,000 gallon pool? And to get it to seven to get it to 7.8, it calls for adding 100 pounds of soda ash to the pool. Now, how would you add 100 pounds of soda ash to a pool? Wouldn't that overload the whole filtration system and cause it to drop out and go all over the pool?

SPEAKER_00: 16:47

It can if you added it all at once, it probably would. Although I suspect that that perhaps 100 pounds might be a little bit more than you would need, but um I can't do that math in my head, unfortunately.

SPEAKER_02: 17:01

But I used your app and it it said close to that.

SPEAKER_00: 17:04

Okay. All right. Well, if you did, then that's fine. It's called the pH alkalinity adjustment tool. And I think every service tech ought to own one. It's not because I make money, it's because it's a great app. And it'll tell you what you need to add to the pool to fix it, uh, to fix the pH and alkalinity. And it costs$8. And it's not a subscription, it's a one-time purchase. So you own it. Uh it's not even an annual purchase, it's once and you own it. Um, anyway, it's a great app. And once you build the pH up just a little bit using soda ash, then you can do it the rest of the way with baking soda and then increase the pH by uh aeration and turbulence. And that way you don't have to add so many pounds of chemicals to the pool. So it's a much much better way to do it. Oftentimes, when you're trying to adjust pH and alkalinity using soda ash, if you add enough soda ash to get the right alkalinity, then your pH is way too high. And if you add uh enough to get the pH up there, then your alkalinity is probably not high enough. So you need probably a combination of soda ash and bicarb to get to the right level. And you can save some money if you simply get the alkalinity where it needs to be and then raise pH with aeration and turbulence. And it raises really quickly when the pH is low. So you can you can do this, it's not difficult.

SPEAKER_02: 18:41

Okay, so you wouldn't put 100 pounds of soda ash in the pool. You would put enough of it in there just to get it up a little bit, and then you would go to baking soda to get the alkalinity to let's say 80 or 90, and then from there you would put maybe a submersible pump shooting water or return jets shooting water up at the surface, and that would raise the pH more than just adding all that product.

SPEAKER_00: 19:03

Yes. And and I have a rule of thumb that I used to do, and it's it's just based on practical practical knowledge and and years of doing it. Well I have to add a really large amount of chemical to it, any pool, except for chlorine, I usually add it in thirds. And so if you need a hundred pounds in a pool, I would add 30 pounds or 40, 30 to 40 pounds. It doesn't have to be exact, just 30 to 40 pounds, give it a couple of hours to get to get uh for the chemical reactions that take place, then add another 30. And it's also a good idea between additions to retest the water. And the reason is that if you were wrong in your calculation, then you don't have to add a bunch of acid to get things back to where they belong. Or, you know, maybe you thought you had a 25,000 gallon pool and it's only a 15,000 gallon pool. So it's it's a good idea to just kind of be a little bit cautious instead of throwing that all in there. Other obvious reason that you mentioned is if you put 100 pounds in there, chances are if you have any amount of calcium in the water, you're probably going to precipitate some of it. Because when you put 100 pounds of soda ash in the pool, you're gonna raise the pH of the whole pool up to perhaps nine. And at nine, you can start to precipitate out some calcium carbonate, even if the calcium level is only of 150 or 200. I would add it in thirds. And and also if it precipitates, it's a very fine precipitate, and it can take a couple of days to clear. And you don't want to do that, you know. So just put a third in there, retest it, uh, make sure that everything's okay. Put another third in, then put another third in.

SPEAKER_02: 21:00

And if you like this podcast, you can of course find more by going to my website, swinging for learning.com. On the banner, click on the podcast icon. There'll be a drop down menu there of over eighteen hundred podcasts for you to listen to. If you're interested in a coaching program that I offer, you can learn more at foogaicoaching.com. Thanks for listening to this podcast. Have the rest of your day. God bless.