Does calcium hardness still matter for fiberglass and vinyl liner pools? Does the LSI still matter? Tyler and Eric discuss the importance of both, especially in non-cement pools. Chalky white discoloration of fiberglass pools and fading vinyl liners are just some of the symptoms of not having enough calcium hardness to balance the LSI year-round.
00:00 - Introduction
01:29 - pH rise should NOT be caused by cement finishes
05:08 - Is calcium needed in vinyl and fiberglass pools?
07:17 - Fiberglass gel coat degradation and chalking
09:25 - Vinyl liner fading
11:04 - LSI and calcium levels always matter, regardless of pool type
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119. Calcium in Fiberglass and Vinyl Pools (w/ Tyler Mills)
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[00:00:00] Eric Knight: Welcome back to the Rule Your Pool podcast. This is episode 119. And today's episode, I'm recording from a place that I've never been in. Tyler Mills' apartment in Phoenix, Arizona. Tyler, thanks for being back on the show.
[00:00:14] Tyler Mills: Thanks for having me again, Eric.
[00:00:15] Eric Knight: Tyler, you know what we're talking about today?
[00:00:17] Tyler Mills: We're talking about fiberglass and vinyl liner pools, which is something I don't have a lot of in this market.
[00:00:23] Eric Knight: Yeah. You cover Arizona, Nevada, Colorado. Not a lot of vinyl liner or fiberglass pools in the Phoenix market. But the big questions that we get on the helpline and you've received some of these I'm sure, is why is my fiberglass pool turning white? Or why is my vinyl liner fading? Or how much calcium should I have in my pool? Because the manufacturers will say, oh, don't have more than 200 parts per million calcium.
[00:00:49] And I'm here to tell you, listeners, the LSI is still the LSI on everything. And that's what we're going to talk about today. Do you have anything you want to bring up before we get into this?
[00:01:00] Tyler Mills: Yeah, last time I was on here, I said something. I think you remember what it was that I was coming for Jarred's job. And I wasn't joking about that. So, it's still going to happen.
[00:01:09] Eric Knight: Well, how prepared are you for this? How many episodes have you listened to?
[00:01:13] Tyler Mills: Five to six.
[00:01:15] Eric Knight: Yeah, you really are coming for his job. We have a very low bar and that's exciting. So this is episode 119 of the Rule Your Pool podcast.
pH rise should NOT be caused by cement finishes
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[00:01:29] Eric Knight: You know what I find interesting? It's this myth that if you have a cement-based pool, plaster, quartz, pebble, whatever. That your pH is going to rise because it's a plaster pool. And we know that the pH does naturally rise, but it's not because of the cement, hopefully.
[00:02:06] Now I'm going to ask you, why does the pH naturally rise, Tyler?
[00:02:10] Tyler Mills: pH naturally rises due to the loss of CO2. And we know CO2 dictates what the pH of that water really is. The amount of CO2.
[00:02:19] Eric Knight: Very good Tyler, so elaborate on that. We know we've got CO2 in the water because we have carbonate alkalinity. And we know that CO2 determines the pH of the water, but why does that make the pH rise?
[00:02:33] Tyler Mills: It makes the pH rise because we know that CO2 is offgassing from that water to equalize with CO2 above the atmosphere. Now, if you've heard our classes in the past, we usually use an analogy to explain this. So let's think of a soda or a beer. So Eric, I hand you a bottle of Coke, and before you open it, is there any bubbles in it?
[00:02:53] Eric Knight: Nope.
[00:02:54] Tyler Mills: Now when you open it and you twist that cap. What noise do you hear?
[00:03:00] Eric Knight: I hear CO2 escaping from the bottle.
[00:03:03] Tyler Mills: And the same thing's happening in swimming pools. It's offgassing two equal to the partial pressure of that atmosphere above it. So over time, less CO2 is in that soda. Therefore it becomes flat, and our swimming pools are going flat all the time.
[00:03:16] Eric Knight: Very good. You are making a run for Jarred's job. Good for you, Tyler.
[00:03:19] Okay. So we do know that the pH does naturally rise due to the off gassing of CO2. That's a fact. The myth is that if you have a cement based pool that it's rising because of the cement. And what we're here to tell you is that's not necessarily true. In fact, we hope it's not true. It can be true if you're running an unbalanced LSI or you're over-correcting with acid and the LSI ever goes red.
[00:03:45] And LSI, of course, if this is your first episode listening, is the Langelier Saturation Index, which is the index that we use to measure the balance of water. If it is aggressive, that water's hungry and it's looking for calcium. So it's going to dissolve it anywhere it can find it.
[00:04:00] In some plaster pools, many I'm sure, if they are mismanaged or they are using trichlor as a primary chlorine, which is acidic, and the CYA gets up, and the LSI gets more aggressive, yes. You could be dissolving calcium hydroxide, which does have a high pH, 12.6, and that will spike the pH. But that's spiking the pH. That's not a natural rise.
[00:04:21] And as we've spoken about in previous episodes, the natural rise of pH takes you up to the pH ceiling. Which, in the Orenda Calculator app is a secondary reading so you can see it. If your pH ever goes over that pH ceiling, something forced it to be that high. And usually that's over-correcting with acid that dissolves cement.
[00:04:40] But how could that happen if your surface is a vinyl liner or a fiberglass pool? So, this is where the myth comes from, and I'm here to debunk it.
[00:04:49] It is not supposed to be the cement that raises the pH in these pools. Natural physics will do that with the offgassing of CO2. Salt systems just accelerate this because they bubble off CO2 within them, due to the hydrogen bubbles, and that creates turbulence and therefore. Um, the pH rises from there.
Is calcium needed in vinyl and fiberglass pools?
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[00:05:08] Eric Knight: Let's get back to the vinyl liner and fiberglass. The thought that is prevalent in our industry is that if you don't have calcium in the material, like in the surface, you don't need as much. Because you don't have to worry about calcium because it's not a calcium surface. So who cares? And we actually have seen this in so many words. I'm paraphrasing, of course, in manufacturer warranty documents for fiberglass pools and vinyl liners.
[00:05:33] I've seen documents that say, don't go over 200 calcium. I think it's all based on the old way of thinking that these pools are a lot more prone to get scale.
[00:05:43] And so you see scale, or at least you see white deposits , and therefore people think it's scale, even if it's not. And that has eventually evolved into a habit of saying, Hey, I want to avoid that problem, therefore, have less calcium.
[00:05:55] We saw the same phenomenon in the Northeast five or six years ago with the crystals. People thought it was scale. And over the years they were tired of opening up the pools to crystals, so they said, I'm sick and tired of this scale. I'm going to dilute my water down and lower the amount of calcium in it so that I don't have scale. Which of course made the crystals worse because it's the opposite of what you should have been doing. It was always an LSI violation.
[00:06:20] So let's talk about what the LSI does to vinyl liner and fiberglass pools. Again, you don't have many here in Phoenix. Let's start with you. What can the LSI do to a cement based pool? Whether it's plaster, quartz, pebble. What can it do if the LSI goes purple?
[00:06:38] Tyler Mills: Well, you'll start to see scale forming, typically in the hottest parts of the pool first. So think tile lines, spillways, things of that nature. Um, I've even seen it so extreme where the pool's pretty cloudy. And the cloudiness actually came from just super-high LSI water.
[00:06:52] Eric Knight: Right. So is actually precipitating calcium in the middle of the water.
[00:06:56] Tyler Mills: It needs to get rid of some of it to put itself back into balance. So it does that through the water.
[00:07:00] Eric Knight: Okay. How about salt pools? What do you see in salt pools?
[00:07:03] Tyler Mills: You see scale buildup in salt cells.
[00:07:06] Eric Knight: Which flakes out and blows past the return and all that. Okay. You ever seen white dust at the bottom of these pools?
[00:07:12] Tyler Mills: I have.
[00:07:13] Eric Knight: Okay. How about plaster start-ups? You ever seen plaster dust?
[00:07:16] Tyler Mills: I've seen lots of it. Yes.
Fiberglass gel coat degradation and chalking
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[00:07:17] Eric Knight: Localized LSI violations. Here we go. So that's what you can see in that type of pool. A fiberglass pool doesn't have any cement in it.
[00:07:25] A fiberglass pool is protected by a gel coat. And a gel coat is made up of polyester resins, pigments, and catalysts to harden it. What happens is, if the water is aggressive, it is looking for calcium. It is starving for calcium. And it's going to start degrading that gel coat. It's going to start gnawing away at it. This is a highly scientific term, Tyler. Just go with it. You live in the desert, so you know this. But you know, like in the Mojave desert, it doesn't rain, and the ground is all flat and cracked? Kind of like those old skin commercials, like, is your skin dried out and cracked?
[00:08:01] Tyler Mills: Yeah.
[00:08:02] Eric Knight: If you were to zoom in with a microscope on a gel coat. It kind of looks like that. And then chlorine can get into those cracks and it could start oxidizing the polymers in there. And they turn white. This is what fiberglass chalking is.
[00:08:17] Now I call it chalking, uh, most people that we've talked to know what I'm talking about when I say it it's that white haze on a fiberglass pool. That is not scale. If it were scale, it would only be at the water line or in the hottest places first, and it would come off with diluted acid and you could balance it and clean it off because it's on top of the gel coat.
[00:08:39] But anybody who has seen this knows this stuff doesn't react to acid. It's a discoloration of the actual material because chlorine got into the gel coat and started oxidizing it and turning it white.
[00:08:51] Huge difference. It is a low-LSI violation. It is not scale. It's the opposite of scale. And unfortunately it's permanent damage. So LSI balance in a fiberglass pool is really, really important. You do not want that water to be aggressive.
[00:09:05] And if you have a fiberglass pool in a cold climate, I'm from Northern Virginia, anywhere, you know, mid-Atlantic and north, those pools will freeze. And if you have less than 200 calcium, you don't have the insulation to get through the winter time and you are bound to have some destruction of that material in the wintertime.
Vinyl Liner fading
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[00:09:25] Eric Knight: And the same thing goes for vinyl liners. I know they're not here in Phoenix, but have you been in markets where you've seen fiberglass and vinyl liner pools before?
[00:09:33] Tyler Mills: Yeah, I have, I was just in Mesquite, Nevada. Went and saw one there and a couple in Colorado, actually.
[00:09:39] Eric Knight: When you go and see those pools, did they have a problem? Like why were you there?
[00:09:44] Tyler Mills: I was called there because they had some issues with cloudiness.
[00:09:47] Eric Knight: Oh, cloudiness. So it wasn't like a fading liner or anything?
[00:09:50] Tyler Mills: No.
[00:09:51] Eric Knight: Okay. We would get a lot of calls about stains on liners, but fading is a big one. Now there's a difference between fading and yellowing. If you have a vinyl liner pool, we're switching gears here, yellowing is typically from exposure to UV light. So long-term sunlight and chlorine.
[00:10:10] Pigment loss, fading, is usually an LSI violation. Because it's actually removing material. People think it's bleaching it out. That's generally not the case. I can't say that it's not part of it. Perhaps it could be, but to actually remove pigment, you need to remove material.
[00:10:28] And as luck would have it, inside your vinyl liner, all of them, they do actually have some calcium carbonate in there. It's not a lot, but trust me, water will find it. And when water takes that calcium carbonate out of that vinyl material, it becomes more porous.
[00:10:44] And when it becomes more porous, it can become wrinkled. Especially with thermal expansion and contraction as the water temperature changes. So if you have a wrinkled liner or you have a fading liner, that is usually driven by an LSI violation. Aggressive water does that. It's not just chlorine. It's not just sunlight. So be aware of that.
LSI and calcium levels always matter, regardless of pool type
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[00:11:04] Eric Knight: The point of this episode. Is to let you know that the LSI matters in all of these types of surfaces. In fact, I would argue it's more important in vinyl liners and fiberglass pools, because there is really no mechanism for water to correct itself.
[00:11:19] Now of course it's a big deal in a plaster pool and you can get discolorations and you can get uneven carbonation and all that. But in those pools, water can correct itself. We are the ones that continue to screw it up. We are the ones who continue to try to beat the pH down to 7.4, because we were told to. We are the ones that try to maintain unreasonable numbers, depending on where we are, without factoring in things like water temperature, or cyanuric acid, or whatever.
[00:11:45] If we're not focused on the LSI, then you have a very high probability of damaging that surface, regardless of what it is. See, water doesn't care about you or me, it cares about its own balance. So either you give it the balance it needs, or it's going to have to balance itself. And Tyler, in a fiberglass pool, it has no mechanism to balance itself. So it just lashes out. It's like you when you were a teenager, right?
[00:12:10] Tyler Mills: That's pretty accurate. Yes.
[00:12:12] Eric Knight: It's just mad. So it starts destroying things. All right. So I'm going to challenge you since you don't really see a lot of these pools. Can you summarize what is fiberglass chalking? And how can they prevent it?
[00:12:26] Tyler Mills: Fiberglass chalking is when there is a bunch of cracks and voids, chlorine getting within them, and oxidizing the actual material and that's where you get the chalking.
[00:12:35] Eric Knight: Right. And what causes that material to crack like that?
[00:12:38] Tyler Mills: Aggressive water. Being aggressive on the LSI. It's unbiased. Doesn't know where it can find the source, so it needs to balance itself back out. So it just starts eating.
[00:12:46] Eric Knight: That's right. That's right. Okay. Vinyl liner. Fading and wrinkling is also caused by a low-LSI violation, right?
[00:12:55] Tyler Mills: Yes.
[00:12:55] Eric Knight: What can our listeners do if they happen to have a fiberglass or vinyl pool, what can they do to be proactive about this and prevent these issues from starting?
[00:13:05] Tyler Mills: Pay attention to the LSI. Make sure you're aware of what the behavior of water actually is. And start with a good foundation, which is calcium. Calcium is stable. We always recommend using calcium as your foundation. And in my opinion, everything from there kind of gets a little bit easier.
[00:13:22] Eric Knight: Well, we talked about it in a previous episode. I don't remember what number it was, but calcium is the bedrock of water balance. Go back and listen to that episode because it depends on your temperature extremes of where your calcium should be to allow you to maintain your LSI and contain your pH.
[00:13:38] That's all a part of the same physics philosophy that we're teaching here. You need enough calcium. So for those of you who do reach out with questions of saying, hey, my manufacturer says don't go over 200 calcium. Have them listen to this episode. Have them reach out to me podcast@orendatech.com. Visit our help center, ask.orendatech.com. This information is real. It's here. It's validated. Check our sources.
[00:14:06] Tyler, anything you want to add before we go?
[00:14:08] Tyler Mills: Nope. I'm good.
[00:14:10] Eric Knight: Cool. It is really hot in this apartment because it's 117 outside. So let's end this. And, uh, fix your air conditioning. I'm Eric Knight with Orenda and HASA. And, um, this has been episode 119. Thanks for your time.