The LSI and chemical dosing results in the Orenda Calculator (version 3.0) are different than before. And they're different from other apps and dosing charts. Eric explains why.
00:00 - Intro
00:44 - Orenda 3.0 features new, improved formulas. Most of the update was about improving the formulas.
01:43 - The LSI reference chart is the basis for most LSI calculators.
02:52 - The old Orenda app extrapolated within the LSI dosing chart to be more accurate.
04:39 - The new Orenda calculator is more true to the Saturation Index, and that's why the LSI results will be slightly different than before. They are more precise now.
05:53 - Dosing calculator formula upgrades
07:20 - You can now select your preferred acid and chlorine types
08:26 - Dry chemicals are by weight, liquids are by volume. This is because dry chemicals of the same volume can have different weights.
09:40 - Use a graduated dry pool chemical scoop that shows you different lines for what one pound of each chemical is in volume.
09:59 - Summary. Thanks for listening!
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75. Why are the LSI and chemical dosing results different in Orenda 3.0?
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[00:00:00] Eric Knight: Welcome back to the Rule Your Pool podcast. I'm your host Eric Knight doing this one alone. This is episode 75. I know you're just craving to have Jarred back on the podcast and he will be on the next episode he says, but it wouldn't be the first time Jarred's played hard to get, and then he just bails on us.
[00:00:20] I'm grouping myself with you on that. We all want Jarred back. But in this episode, I'm going to talk about why the Orenda 3.0 app has a different LSI value than our previous app. And more importantly, why it's going to be different than pretty much everywhere else you're going to look at an LSI calculator.
[00:00:37] So let's get right into it. Episode 75, let's go.
[00:00:44] It's no secret that in Orenda 3.0, we changed our formulas. We upgraded 'em in a major way. In fact, the bulk of the update actually was improving the formulas. And I suppose it would provide more context for you if you knew how the old formulas worked, because this is probably how other LSI calculators work as well.
[00:01:23] If you go onto blog.orendatech.com and search LSI. You can also do this from the Orenda app. Just go to the main menu, blog, top button, search LSI. You're going to find an article that says understanding LSI. In that blog, and several others, by the way, pillar one, I believe, there is a reference chart.
LSI factors chart
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[00:01:43] Eric Knight: This is the LSI factors chart. we made it look a little prettier, but this information is open source. It's in the CPO book. And so you can look up, based on your chemistry factors, like water temperature, calcium hardness, alkalinity, et cetera. Each one of those values is assigned a multiplier, a factor. But the problem with this chart is there's a lot in between what shows up on the chart that are not represented.
[00:02:10] So I'm going to take calcium hardness, for example. The parts per million that are represented on the chart go as follows: 5, 25, 50, 75, 100, 150, 200, 300, 400, 500. And that's it. Nothing in between.
[00:02:32] Well, that's great if you happen to land exactly on one of those numbers. But nothing between 200 and 300? Or 300 and 400? Almost every pool in America is going to be somewhere between 200 and 400. And yet there are only three factors represented there. For a potential of 30 different numbers, in increments of 10 parts per million.
Orenda's old LSI formula
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[00:02:52] Eric Knight: So what the Orenda app did years ago to make this more accurate, was we extrapolated and assigned a multiplier to every single increment of calcium hardness based on 10 ppm.
[00:03:05] Okay, so 100, 110, 120, etc., all the way up and all the way down, technically. Everything was assigned to value. So we extrapolated between what this chart shows. And that made it a lot more accurate.
[00:03:18] We did this also with alkalinity, we did it with cyanuric acid, with water temperature. Like water temperature, for instance, I'm looking at the chart now. 32 degrees, 37, 46, 53, 60, 66, 76, 84, 94, 105. Nothing in between? Really? I mean, are your degrees exactly that? So we wanted to assign a factor for every single degree in Fahrenheit and Celsius. And we did. That's how it was done. And that's why the Orenda app has always been traditionally the most accurate LSI calculator. Because we extrapolated within this chart.
[00:03:56] Well now it's way better than that. Because this chart, actually, if you look at the history of the LSI, was simplified over the decades and adapted to swimming pools. Dr. Wilford Langelier in, I believe the 1930s, was talking about boiler systems.
[00:04:16] The LSI was not originally made for swimming pools. It was about the propensity of water, in closed water boilers to either corrode or form scale. It was then adapted to other uses over time. Long after Dr. Langelier had passed away. This chart is a result of a lot of those adaptations and simplifications.
[00:04:39] We went back to the roots. And we had help to do it. We wanted to get to the most accurate saturation index we could possibly have. And beyond that, as we've mentioned in previous episodes about this app, we had to include borate, even though we don't advocate for the use of borate, it does affect the LSI. Specifically at higher pH's.
[00:05:03] Cyanuric acid has to be included. So how specific can we get? Well, to give you an idea, this LSI formula is over 300 rows in a spreadsheet. Yeah. Good luck converting that into code. It took a long time. But in order to do it, we needed to be able to extrapolate out to six decimal places. Now, what you see on your screen is rounded down to two decimal places. But this is a robust formula.
[00:05:33] It really is. And we're very confident in it. We've tested it. It is slightly different than the previous Orenda results, but they're close. Okay. It's just a little bit more on the money.
[00:05:45] It's going to be different than any other calculator that you use. It's going to be different than the charts. This is why.
Chemical dosing formulas
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[00:05:53] Eric Knight: All right, now that we talked about the LSI let's move on to the dosing calculator. The dosing calculator is still showing the difference between the left dial and the right dial.
[00:06:04] And if you're going to make a change, let's say you're going to decrease your pH. It will now show you what that will do to your alkalinity. And I said, I think two episodes ago, when we talked about this app, this was kind of the Mac daddy of features. It is predictive alkalinity. It's going to tell you where your alkalinity should be if you do that amount of acid. Assuming you know the exact volume of your pool.
[00:06:31] Now that said., If you don't measure and dilute that acid, that number doesn't mean much. And if you don't know the accurate volume of the pool, it doesn't mean much either. But assuming all of those things are done and done correctly, this is a very precise alkalinity of what your pool is going to have next week, or the next time you treat it. Because it's telling you exactly how much alkali is going to be removed from your water or neutralized by the acid that you're adding to reduce the pH.
[00:07:00] It's a very cool feature. But it only shows up if you're only reducing pH, not alkalinity too. Because if you're reducing both, the alkalinity number is going to override that. And by the way, there's a hyperlink on it for decrease pH and decrease alkalinity. Tap those before you dose, it'll tell you what the calculator's reading out. We thought that would help.
[00:07:20] When we're talking about these chemicals in general, we've done a couple of things. We added toggles for your preferred acid and your preferred chlorine. Let's say you select liquid chlorine. It's going to give you both strengths that are common on the market. 10% and 12.5%. Slightly different, you know, but they're both liquid chlorine.
[00:07:42] Same with Cal hypo. So we have 65 to 68% and we have 70 to 73%. The reason for that that has to do with how the product is labeled. So your percent available chlorine is slightly different than the chlorine by weight. So some Cal hypo may say it's 65% and some may say it's 68%. 68% would be by weight. 65% would be by percentage of free chlorine, or I'm sorry, by percentage of chlorine available. Uh, it's the same product. It's literally the same thing. It's just labeled a little differently. So that's why we did it that way.
[00:08:19] But let's say you're going to add calcium and you're going to add chlorine.
[00:08:26] We have taken into account the densities of these products. So calcium chloride has a given density depending on the purity. So if you have 77 to 80% flake, that's a different density than 94% prill. That needs to be taken into account. So all of our dry chemicals are now measured by weight. All the liquids are measured by volume, like fluid ounces or gallons.
[00:08:50] I didn't know this. But I just learned during this app update, that volume is different from weight in a dry chemical. We may do an entire episode about this because, um, if you have, let's say a cup in your kitchen. Like an 8 oz cup. You want to take a cup of flour and whatever you're going to do.
[00:09:10] If you take that cup and scoop sodium bicarb, baking soda, it is going to weigh something different than if you were to take a scoop of DE, or a scoop of calcium chloride, or a scoop of sodium bisulfate. The same cup is going to have different weights to it. Good to know. That's why it's done by weight. So at a pool distribution store, or if you're a homeowner listening to this and you can get it on Amazon very easily.
[00:09:40] Get a dry chemical scoop that has graduated lines for each product. It'll tell you, you know, one pound of this chemical is at this line. One pound of this next dry chemical is at this line. One pound of another dry chemical is at this other line. Use that scoop. That's going to be how you're going to be the most accurate.
Summary
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[00:09:59] Eric Knight: So anyway, this has been episode 75 of the Rule Your Pool podcast. Thank you so much for listening. It's kind of hard to believe we've done 75 episodes. And don't worry fans, Jarred will be back in the next one.
[00:10:10] But if you have an idea or something that you want us to research or cover on this show, please email us podcast@orendatech.com or check out our help center, ask.orendatech.com.
[00:10:24] I'm your host Eric Knight. Until the next one, thank you so much for listening. It means a lot. Take care.