If you divide up pool chemistry, there's really two subcategories of it. There is sanitization (which is water, clarity, cleanliness, and safety) and there is balance. Is your pool scaling, etching, filled with calcium dust or crystals? All of those problems are LSI violations. They can be completely prevented simply by balancing the LSI and keeping it balanced. Following the conventional wisdom of range chemistry doesn't guarantee that you will have balanced water. But following the Langelier Saturation Index does. In the first three episodes, Eric and Jarred covered Total Alkalinity and pH. Those are two of the six factors of the Langelier Saturation Index (LSI). In Episode four, they cover the rest of the LSI and what you need to know about it. The LSI is the objective measure of water balance. Eric and Jarred will talk about what that means. There are six factors, and they will tell you what you need to know about all of them.
00:11 - Episode Takeaways
01:51 - Water Balance vs Sanitization
05:38 - What is the LSI
09:58 - The six factors of the LSI
11:56 - Water temperature: the most ignored factor?
15:17 - Total Dissolved Solids (TDS)
18:20 - A (Very) Brief History of the LSI
Connect with Orenda Technologies
Relevant Blog Entries
ORP and LSI: The Future of Water Chemistry
Eric [00:00:00] Hey, everybody, welcome back to the Rule Your Pool podcast. This is Eric Knight, your host, and our co-host is Jared. Jared, thanks for being with us.
Jarred [00:00:09] Happy to have another episode here.
Eric [00:00:11] [00:00:11]Yep. Episode four. So in the first three episodes, we covered Total Alkalinity and pH, a little bit of an overview and then the next two episodes were about alkalinity in depth. And then pH and those are two of the six factors of the Langelier saturation index. So today in Episode four, we're going to do an overview of the rest of the Langelier saturation index or what we call the LSI. And since we've already covered two of those six factors today, we're just gonna do an overview of the rest of it. And then the following episodes from here, we'll dive into those other four factors like water temperature, et cetera. So there are three takeaways from today's episode. We're going to talk about water balance, not water cleanliness or anything like that. The LSI is the objective measure of water balance. We'll talk about what that means. The second takeaway is there are six factors, not just the two that people test most often. So if you're only testing those two, you're not getting the whole story. And we're going to, for the third take away, really dove into the neglected ones. So without further ado, this is Episode four of The Rule Your Pool podcast, The Introduction to the LSI,[71.2s]
INTRO [00:01:27] Welcomee to Rule Your Pool, the podcast by Orenda that explains and simplifies pool chemistry. So then anybody, regardless of experience can understand it. I'm your host, Eric Knight, bringing clarity to these subjects so that you can bring clarity to your water. If you're ready to rule your pool, let's go.
Eric [00:01:51] [00:01:51]So if you're going to divide up water chemistry or let's say pool chemistry, there's really two subcategories of it. There is sanitization, which is kind of water, clarity, cleanliness, safety, algae free, germ free killing germs and all that. [17.1s] That is one discipline, and it's largely unrelated to what we're talking about today. So you have this sanitization, which is does the water look good and you have balance. And a lot of people will say, oh, I've balanced water chemistry because they're within the ranges that textbooks say. Or if you look online, the pH would be 7.4 to 7.6. And those are ranges 80 to 120 alkalinity, 200 to 400 calcium. And we call that at Orenda range chemistry. But [00:02:40]range chemistry does not always mean balanced chemistry. [3.2s] There's a big difference. So we had Orenda we teach in LSI based water treatment philosophy. We have to understand the LSI first and range chemistry second. And to be honest with you, depending on where you are and depending on the time of year, it may be physically impossible to have balanced water within the textbook ranges and the LSI is what teaches us tha. Because I you know, I've only been doing this a few years. But Jarred, you've been doing this for many years, longer than I have. And Harold's been doing it since 1984. Nobody really knew that. Nobody really knew there was a difference, that it was extremely difficult to have balanced water in the wintertime.
Jarred [00:03:27] People just assume that if you're within the industry ranges, you shouldn't have any problems. You followed the letter to the T. You're within the rules, so therefore you shouldn't have any issues, which we found out obviously is not the case.
Eric [00:03:41] It's definitely not the case and starts to explain a lot of the same problems that keep happening. Season after season. And one of those examples is like winter crystals in the Northeast and the Midwest. Everyone thought it was scale. Well, now that we have a firm understanding of the LSI that is completely explained by the LSI and it's totally preventable.
Jarred [00:04:00] We keep referencing LSI. And I know when they open you said it was about water balance. But more specifically, just so our listeners understand, we do know this revolves around calcium, OK? The Langelier saturation index is the calcium saturation, whether you're under oversaturated in the water and that measurement. We do understand that. So.
Eric [00:04:21] Yeah. Yeah. Well, I'll get into that. In fact, the LSI some there are other indexes or indices. If we want to be official. There is the Hamilton Index, there is the calcium saturation index, which is pretty much identical to the Langelier saturation index. And there's the Reisner corrosion index. They're all very similar. If you're following one of them, good for you. That's better than just winging it and going with ranges. They all take temperature into account. They all take into these other factors. The LSI is the industry standard. That is what we have put into the Orenda app. If you don't have the Orenda app, it is free. It's it's in the App Store and Google Play and it will help you understand the LSI so that when we make references today, when Jared and I are talking about the calculator, that's the Orenda app we're talking about. So when we say the number goes red, it means that the LSI is low and it's etching. And when it goes purple, it's too high and it's gonna be scale forming.
Jarred [00:05:15] We have a pretty cool video that explains what is the LSI, too.
Eric [00:05:19] Well, we do. Well, we've got those videos and we will elaborate more. And so let's keep this episode focused on just an overview of what the LSI is. As Jared mentioned, it's about water balance and that is the balance of how saturated your water is with calcium carbonate. I'll repeat [00:05:38]that: the LSI measures how saturated your water is with calcium carbonate. [5.6s] If you have too much, it'll start precipitating out. If you don't have enough, water will seek it and it will find it anywhere that it can. And it'll take it. This is like etching. If you have a plaster surface and starts getting rough and you start losing cement or tile grout, the water took that calcium because it needed it.
Eric [00:06:04] [00:06:04]The LSI is an index based around zero point zero. [4.7s] All right. That is perfectly balanced. Saturated water and the safe zone goes down to as low as minus zero point three zero. So minus zero point thirty two, positive zero point three. Anything in there is considered balance and the water is happy. Of course, zero point zero zero is perfection. But we don't live in a perfect world and factors change. As we discussed in the last episode, pH will naturally rise over time. So your LSI is going to be changing every day anyway. The key is, can you contain it within that window?
Jarred [00:06:42] Have you ever seen charts that go to plus and minus point five?
Eric [00:06:47] I have. So depending on who you ask - uh great question. I've never seen it negative point five. I have only seen positive point five. Like the National Plaster Council accepts something a little bit higher to positive point five. And that's due to the solubility of calcium hydroxide. So it'd been minus zero point three to the high end of zero point five. And largely from my understanding and I guess I'm publishing this, so I guess I'll be on record. But it's my understanding and I don't know for sure, but that has to do with startups primarily.
Jarred [00:07:22] I would say it's good practice. Well, to stick between plus and minus point three. Let's make it easy.
Eric [00:07:28] Right. That's what most sources say. And, you know, [00:07:31]if you're gonna err high, I understand their position. If you're an err high err to the scale forming side, totally get it. Because scale doesn't hurt anything. You know, maybe our feelings [9.2s] some somewhat our reputation, but it doesn't actually hurt the surface of the pool. You can always clean scale off. Have now, in your experience, Jared, [00:07:50]you've cleaned a lot of scale because you live in Texas, your cleaning pools for many years before Orenda. Where were you seeing it? [6.0s]
Jarred [00:07:57] Always on the spillway and the timeline.
Eric [00:08:00] And how did you address it?
Jarred [00:08:02] It's funny you mention it, because actually today I did in a treatment with SC-1000 on my pool to get rid of the scale on my spillway. And I actually took some videos and pictures and I'll send that out for publication at some point in time. But that's exactly why it falls out: right on the spillway and between my rocks down on the tile line. Always.
Eric [00:08:23] Now, before Orenda, before you understood the LSI, what was your strategy to get rid of that stuff? Were you physically grinding it off and sanding it down or what?
Jarred [00:08:33] I have done a lot of called scale sticks, basically, and they look like little rubberized sanding balls on the end of a pole. You can put them on the end of a pole and they do a pretty good job of scraping off thin layers of scale, but if you have a real thick build up its chisels and and screwdrivers.
Eric [00:08:52] And there's and there's been blasting, there's all sorts of there's an entire business around removing calcium deposits and swimming pools. In reality, for those of you listening, [00:09:01]all of those problems are LSI violations. They can be completely prevented simply by balancing the LSI and keeping it balanced. [6.8s] So when we're talking about water balance, again, that's the LSI that has nothing to do with chlorination. You can have a perfectly balanced pool that's full of algae and gross. It could be balanced because it's about calcium saturation. Now, it's not optimal. We don't want that. We have to do both. But we have to prioritize the balance of water. That's the hard part. Sanitization is easy. That's just keeping your chlorination and CYA in check. But balance is a real art. And that's what the calculator on the Orenda app helps you really do, because you can see in real time where your numbers are. So don't confuse the LSI when we say water is balanced with clean or safe to use. It's two separate disciplines. And that brings us to our second takeaway.
Eric [00:09:58] [00:09:58]There are six factors to the LSI. The six factors are pH, alkalinity, calcium hardness, total dissolved solids, which includes salt and cyanuric acid and water temperature. [11.2s] And if you're not testing all of those every time, that's fine. You don't need to test them every single time. That might be overkill. Things like calcium hardness don't really move much. So maybe once a month, every third week, whatever you find appropriate, you don't have to test that all the time. Same as cyanuric acid. If you are using Trichlor or something where you're CYA is climbing up every time you put more chlorine in, you might want to check your CYA every third or fourth week and just understand that the higher your CYA , the more aggressive your water. And that is the same for total dissolved solids. So if you have a salt pool, that is going to be a more aggressive pool, even though your pH is going to rise because of the salt chlorine generation process. Your salt cell will raise the pH in your pool. But by and large, the higher level of total dissolved solids will bring your LSI down. So you've got to be aware that you have to manage a salt pool differently than a cal-hypo pool or liquid chlorine pool. And let's - I know there's all sorts of nuance in this, but a gallon of liquid chlorine is going to leave behind quite a bit of salt, too. So over time, a liquid chlorine pool will have a lot of TDS in it as well. So just be aware that all these things matter. You should probably test CYA, calcium hardness, and total dissolved solids - What would you say, Jarred? Monthly?
Jarred [00:11:31] I'd say at least monthly.
Eric [00:11:33] At least monthly. That way, you know, that's half of the LSI right there. The other three factors you should check, probably weekly. Alkalinity, maybe every other week, but you should definitely do pH every week and water temperature every single week. And that's leading into our third take away, which is the neglected factors and.
Eric [00:11:56] [00:11:56]Water temperature is probably the most neglected, forgotten about factor on the LSI. [3.8s] I mean, how many homeowners have a thermometer in their pool on a string? Hopefully it's a lot. Hopefully it's everybody. And after you listen to this, if you don't, it's like 10 bucks. Get a thermometer. Know what the temperature is in your pool because that is the moving baseline of the balance of your water. Your pool in the summertime will need very different chemistry than it will in the wintertime because the temperature difference.
Eric [00:12:26] Jared, you're in Texas. How cold will your water get in the wintertime?
Jarred [00:12:30] It'll get into the 40s, low 40s depending on the month. But I'd say just to elaborate on a point that you had: check every pool. I mean, just my pool specifically. It's 85 degrees today. Well, I have a pretty moderate amount of trees around my pool, so it stays a little shady, which is good. But I have a neighbor that's down the street who has even more trees than I do and his pool is at least five degrees colder than mine, even though we're in the same neighborhood, same place, same everything. You can have dramatic changes or differences in water temperatures no matter if you're in the same area.
Eric [00:13:11] Yeah, we're big advocates for having a thermometer and every single pool. And if you're a pool pro listening to this, have a thermometer with you, with your test kit. Just know what that temperature is and put it into the calculator because it moves your baseline. It is the most neglected factor. Hands down. And [00:13:27]if you know your temperature, you can predict where it's going to go. [2.5s] I'm from the Washington, D.C. area. Every year the pools are going to freeze everything north of D.C., you can guarantee the pool will freeze at least one day in the wintertime. So you know what the worst case scenario is. You in Dallas don't have that luxury. Now, granted, it's more aggressive where I'm from, but at least we know the worst case scenario so we can predict that that temperature is going to drop and therefore, we have to have a strategy to accommodate for that, because the colder the temperature, the more calcium that water is going to be hungry for, according to the LSI. So we have to adjust our strategy based on temperature. It is very neglected.
Eric [00:14:08] The other neglected factor. I would say that, I mean, cyanuric acid and TDS are both neglected. But the one that most people don't even think about measuring is total dissolved solids. Salt is a part of that. We actually just published a blog about total dissolved solids, salt, all minerals, all alkalinity, cyanuric acid, basically everything that gets dissolved, a little bit of metals. But they don't really there's not enough of them, hopefully, to really make a big swing on it. But all that stuff accumulates over time and it makes the water aged. That's what they say. It's oh, it's aged water. It's three years old. It's four years old. And while it's not a huge deal in places that you can drain and dilute, it's a really big problem in places like Southern California during a drought season because you can't drain and dilute. You have to look at that total dissolved solids number, regardless of what it is, and you have to account for it. What are your thoughts on that, Jarred?
Jarred [00:15:06] I agree and I get a lot of calls on that, specifically when people are wondering about our calculator because our calculator says TDS/salt. And just so people understand, [00:15:17]the TDS is a cumulative number of all of it. So you need to put all of it into that level that you input. [7.3s] Now, the reason why we haven't broken up into TDS and salt is because if you wanted to go from zero salinity to 3400, which is required for most salt cells, it'll tell you on the desired side how many pounds of salt to get there. That's why that's there, why it's broken up. But for the LSI, you need to input the total TDS number, which includes the salt.
Eric [00:15:48] Yeah. And the and the other thing is most people don't think about salt as a factor that counts on the LSI. So if you have a salt pool. The other reason we have it's a salt slash TDS is for those people who don't have a TDS metric. If you have a salt pool, start with the salt number at a minimum, and then add your alkalinity and your calcium to it and you're going to get pretty close. It's not gonna be exact, but you're going to get pretty close.
Jarred [00:16:12] Just as an example. Had thirty-four-hundred parts salt and you had a 300 calcium and a hundred alkalinity. You're going to have thirty eight hundred roughly tedious. That's the number you would input into the calculator for the LSI.
Eric [00:16:24] Right. And that's a huge difference from 200. I mean most tap water's probably three to five hundred TDS. And then I was actually just looking when I was researching for the article on TDS that the textbooks say you don't want more than 15 hundred over whatever the tap water is. OK. Makes sense. But then the same textbook says, wait. But but. But but. But if you have a salt pool. You just add 15 hundred to the top of your salt number. So to me, it kind of throws that whole thing out of the window. Like, what were we worried about staying under 2000 for? Like what we already as a baseline start at thirty five hundred and then we add 15 hundred to that. So [00:17:07]a high TDS is not necessarily a problem. [2.4s] What I'm saying at least for balance, is you just have to account for it. You're gonna need a little bit more calcium, which is kind of a juxtaposition because more Kalsi will actually raise your TDS further. You just need to account for the higher TDS. And most people don't. And therefore they have more aggressive water than they think. So the way you can combat that is get a TDS meter and read it. Use it. Do the same thing with a thermometer. So anything else you want to add? This is all I had for this episode cause we're gonna get into water temperature TDS cyanuric acid. We're gonna cover these in the next four episodes.
Jarred [00:17:47] No, not really. Mainly just a people - And we'll get into that, like you said - people need to understand what chemicals they're putting in and what impact those chemicals have on the TDS and other parameters that we manage because they definitely, definitely come into play. Not necessarily today, but two years, three years, four years from now, these things definitely add up and become problematic if they're not managed properly.
Eric [00:18:12] Yep, absolutely. So this was an overview of the LSI, the Langelier saturation index. And before wrapping up this episode, [00:18:20]I guess we should tell you why it's called that. Dr. Wilfred Langelier in the 1930s came up with this index because he was trying to explain scale formation in pipes specifically of closed water boiler systems. [14.5s] So these pipes with hot water, you'd they would get scale calcification inside their pipes. And he came up with this index. It has since been adapted to the swimming pool business with cyanuric acid. But we don't need to get into all the history there. What we do know is it is a very, very reliable way of knowing how balanced your water is. It is objective. And as long as you measure accurately, it has no opinions. You're either balanced or you're not. And then you can build your strategy with it. So, again, the saturation index is about balance. Not about water clarity or sanitization. And there are some neglected factors like TDS and water temperature. And in the next few episodes, we're going to discuss water temperature, calcium hardness, total dissolved solids (including salt) and cyanuric acid, so that you can get a better picture of what these six factors do to your water balance. So this has been Episode four of The Rule Your Pool podcast. I'm Eric Knight here with Jarred Morgan. Thank you so much for your time, Jarred. Anything else?
Jarred [00:19:42] Nope. Thank you all. And look forward to being back on future episodes here to explain these topics. Awesome. Take care, everyone.
OUTRO [00:19:50] Thank you for listening to Rule Your Pool, a podcast by Orenda Technologies. For more information on what we discussed in this week's episode. Check the links in the description or visit www.orendatech.com. I hope you find this show valuable enough that you tap that subscribe button and share it with your friends. You can also like us on Facebook and social media. With our help, you'll be able to rule your pool without overtreating of the chemicals wasting money. I'll see you next episode.