"Man, let's just get real. That's a pretty sexy way of saying I have metals. Agree?" The boys are back in town and spilling the Tea on TDS (total dissolved solids). No feelings are spared as Eric and Jared cover such frequently Googled and Search Engine Optimized Topics as, "What is Total Dissolved Solids?," "total dissolved solids in water limit," "how to remove TDS," "total dissolved solids meters," "how to measure total dissolved solids in water," and more!
01:03 Episode Takeaways
02:52 What does "Dissolved" mean anyway?
06:12 Mineral Systems: Just Sexy Metal?
06:44 There's a difference between being in solution and being in suspension
07:38 are phosphates part of TDS?
09:36 TDS (total dissolved solids) Limits
12:01 What is "In Suspension"
14:19 Accumulation and Evaporation
16:25 TDS actually lowers the LSI
22:02 TDS meters are not that expensive. (Total dissolved solid meter cost)
24:48 Wrap Up
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Resources
Connect with Orenda Technologies
Eric [00:00:00] Hey, everybody, welcome back to the Rule Your Pool podcast. This is Episode seven. I'm your host, Eric Knight. And with me as normal, Jared Morgan, the co-host. Jared, thanks for being here.
Jared [00:00:11] Happy to be here. And for those of you not watching, but listening... Eric and I surprised each other by wearing the exact same shirt on this podcast -
Eric [00:00:18] Twinzies!
Jared [00:00:18] Uh-huh.
Eric [00:00:18] Twinzies. And, you know, we didn't want to do this whole who wore it better thing, but I'm pretty sure it's Jared. So anyway, today's topic is continuing on our theme of the Langelier saturation index, the LSI. In the last few episodes, we've covered pH, Alkalinity. We touched on carbonate alkalinity, water temperature, calcium hardness. And there's only two factors left Jared. We've got today's topic, total dissolved solids and the next episode, which is going to be cyanuric acid as it pertains to the LSI. So today, Total Dissolved Solids. There's just a few takeaways and I'm going to run through real quick and then we're going to get into it. You're ready to go?
Jared [00:01:01] I think this one should be pretty short and sweet.
Eric [00:01:03] [00:01:03]We hope so. Famous last words. So first, TDS, it includes everything that is truly dissolved. But it does not include things that are in suspension. And there is a difference. But dissolve. We're talking salts, minerals, metals, ions like bicarbonate, carbonate. Basically just about anything that gets dissolved in water is going to count towards that total. Number two: TDS limits. You know, you hear the textbook, "you shouldn't have Fifteen hundred parts over tap water..." Or whatever. They're pretty arbitrary in Orenda's opinion because if you have a salt pool, all those limits go out the window anyway. And there have been studies that show that chlorine efficacy does not go down with higher levels of salt necessarily. So they're pretty arbitrary. I don't know why there's TDS limits, but there can be problems at very high levels. So we'll touch on that. Other third takeaway is TDS lowers the LSI. The higher your total dissolved solids, the more aggressive your water. And that's kind of counterintuitive because calcium hardness and alkalinity go into that number. When they go up, the LSI goes up. But if the TDS is too high, it will actually drop the LSI. And the final thing is how to remove TDS. So Gerardi ready to get into it? [74.4s]
Jared [00:02:19] Let's Do it.
Eric [00:02:19] All right. Episode seven of The Rule Your Pool podcast, Understanding Total Dissolved Solids. Here we go.
INTRO [00:02:31] Welcome to Rule Your Pool, the podcast by Orenda that explains and simplifies pool chemistry so that 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, then let's go.
Eric [00:02:52] [00:02:52]So let's start with what we mean by the word dissolved. [3.0s]
Eric [00:02:57] Water is considered the universal solvent. It can dissolve just about anything. And in swimming pools, it's no different. A lot of things can be in solution in water. As it pertains to swimming pools, the main things that go towards this total aggregation of everything that's dissolved, the main things are minerals and salts. Some people confuse the two. I used to because, you know, table salt looks like a mineral. So minerals and salts, the common minerals by far and away are calcium and magnesium. And there's a lot of variations of salt. Of course, we have normal sodium chloride, which is salt. In a salt pool, of course, this is there. But if you're using liquid chlorine, Jerry, what's the byproduct of using liquid chlorine?
Jared [00:03:46] That would definitely be some salt in liquid chlorine.
Eric [00:03:50] And as we've been looking at the textbooks, which all of you can find online, there's plenty of them out there, depending on what you read. You actually increase for every gallon of liquid chlorine in ten thousand gallons of water. Your TDS goes up 30 parts per million, most of which is salt. So we could look further into that of how much of that is salt and how much of that is other things. But most of it's salt. So you may not have a salt pool, but if you've used liquid chlorine for several years, there's a good chance you've got a lot of salt in that pool.
Jared [00:04:25] I've run into it many times with especially parts of the country that use bleach as a primary sanitizer. Florida comes to mind specifically when you go to a pool and you check the TDS and it'll be 5000 parts per million on a TDS. You're like, whoa, that's really high, which granted, that is pretty high. But these people don't have a salt cell on their pool, so they're thinking they have a, you know, liquid chlorine, you know, pool and they're doing doing what they're supposed to do. But then they realize their TDS creeps up really high. Really fast.
Jared [00:04:57] Mm hmm. And there's a lot of things that leave behind TDS Salt being the most common byproduct. But even if you're not using a salt chlorine generator, where you actually add in the salt yourself, if you use liquid chlorine, as we said, 30 parts per million per gallon per 10000 gallons, that adds up pretty quick. But how about cal hypo? Use this Cal hypo granular shock, that's 12 parts per million left behind, four of which is pure calcium hardness.
Jared [00:05:25] Which me personally and us, I would think, we tend to favor the calcium level being a little higher. So that's not a bad thing in my book. But I can see where if you're running into, let's say, the desert in Arizona and you're evaporating a lot of water and displacing it and refilling with a lot of calcium, you might have a little more hesitancy to do that.
Eric [00:05:44] Right. Accumulation is really what we're concerned about on this topic. Accumulation and its impact on the LSI. So TDS. It doesn't just include metals, minerals and salts. It includes cyanuric acid. It includes nitrogen compounds. It includes ions like bicarbonate and carbonate alkalinity -
Jared [00:06:01] You said something.
Eric [00:06:02] Uh oh what did I say?
Jared [00:06:02] You something in there that I think is important to touch on. You said it doesn't include just metals, no minerals. I think that's something that we need to just touch on real quick because [00:06:12]people have the perception that 'I have a mineral system' or 'I use minerals in my pool.' Man, let's just get real. That's a pretty sexy way of saying I have metals. Agree? [8.9s]
Eric [00:06:23] Yeah. Because most minerals are actually metals, magnesium and calcium. The most common minerals in pools, those are alkali, earth metals.
Jared [00:06:31] And then you can add some silver and some copper and some other things that have disinfecting properties. And then we just lump them all into this nice word that says minerals.
Eric [00:06:40] Right. And there's a difference between - now now that we're on that little spider web trail. [00:06:44]There's a difference between being in solution and being in suspension. [2.4s] So sequestered metals use a sequestering agent or something that actually puts metals in suspension, which is not quite into solution. It makes it easier to filter them out, which is great if you're trying to remove metals, sequestering agents or the way to go. But chelation, which is what we do, we do SC-1000. That individually binds ion by ion singularly and it keeps metals in solution. So a lot of those mineral systems are chelated metals that have disinfection abilities, but they can't be oxidized, at least until the chelant breaks down. So there is a difference between the two. But in realistic terms, unless you're using a mineral system on your pool, you hopefully don't have nearly enough metal for this to make a noticeable impact on your TDS. It's kind of like phosphates. People ask us all the [00:07:38]time, is phosphates part of TDS? [1.2s] Even if it is, it's such a small number. We're talking about parts per billion. So you'd have to have two thousand parts per billion of phosphates - pretty high number - to have two parts per million to your TDS. So, no, is it going to make any impact? Not noticeably.
Jared [00:07:55] The people that use the mineral system. They have a little more control over what's going in. I was more talking about the people that double down on using a mineral system than they use a copper-based algaecide or a silver [00:08:06]algaecide. [0.0s] And they're just compounding these things that are going into the water that they add up. And they do get in the way which is contributing to the overall TDS, just like the salts in the calcium and everything else that we're talking about today. So just wanted to make sure we clarify that minerals and metals and all these things, they play together.
Eric [00:08:26] Well, there's also organics, non-living organics, most of which is in suspension. Very little of oils, grease, body butter, all that. You know, that's kind of a gross term. But lotions, hair gel sunscreens, very little that would ever get into solution. We're not chemists, so we can't say how much of what can actually get truly dissolved to be a part of TDS. But we do know that [00:08:51]organic can actually impact the test readings for TDS [3.2s] because [00:08:55]you measure TDS using a conductivity meter. An electrical charge. [5.2s] Because again, most of it, the vast, vast majority of TDS is actually going to be minerals and salts which do impact conductivity. So we've asked Richard Falk about [00:09:13]does cyanuric acid actually count towards TDS? He says yes, but it's not easily measured because it doesn't impact conductivity the same way that calcium or salt would. [9.2s] So it's kind of hard to nail down. But technically, yeah, it's a dissolved solid that stays in the water. So without further ado, let's move on to point number two.
[00:09:36] [00:09:36]They have limits on TDS. [0.8s] I've got the textbook right in front of me and it says You should not have more than fifteen hundred parts per million TDS over your tap water chemistry. Number one, that requires testing your tap water. And then add up to fifteen hundred parts per million. That's kind of unrealistic. If your tap water has low calcium hardness and alkalinity, which we see all over the country for the most part, you know, we do these startups. We gotta raise - right out of the gate, we've got to raise our calcium up. We've got to raise alkalinity the next day usually. And the chances of us staying under fifteen hundred parts in the first two years, they're pretty low, especially if we're using liquid chlorine or cal hypo. What are your thoughts on that as a pool owner? Jared, speak up to that.
Jared [00:10:23] I was just going to say back to my example of Florida or California, for that matter. When you're using liquid chlorine as a primary sanitizer, you can have way over three, 4000 parts per million in your pool and no time.
Eric [00:10:37] Well, no time. Meaning like a season or two. It's not going to happen overnight, but it will rise. But there's this stigma that goes along with. Having high TDS as if it's oh, it's it's the reason for cloudy water or my chlorine won't work or algae will happen. That's mostly not true. It's just it's been debunked. I've done a lot of research before doing this podcast. I'm not going to pretend that I know nearly as much as the people who wrote the books. But there's a lot of conflicting information. And the opinion that I tend to take is the guy who was actually measuring it using conductivity and studying and over many, many years. And what TDS actually does is it creates a detriment not to necessarily chlorine efficiency. It's supposedly it could interact with ORP, but it's really a detriment to the LSI. It makes your water more aggressive. Truly dissolved things are invisible. You can have a lot of it - look at the ocean. The parts per million of salt in the ocean, I've heard different statistics, but it's it's over 30 thousand parts per million salt. The pool is three thousand to thirty five hundred. So right there you have an exponential increase by 10. I've heard some numbers that are fifty thousand. And yet the water can be clear and you can go scuba dive in it. So there's a lot more to it. [00:12:01]What what clouds up water is things that are in suspension. [2.4s]
Eric [00:12:05] [00:12:05]For instance, here's a perfect example, Jared. [2.3s] We have a high LSI violation. You put too much Cal Hypo in and your pool starts to cloud. That cloudiness is calcium carbonate, right? It's coming out of solution. So it was in solution and it was invisible. Now you start to see it. It clouds up your water and turns white. Or if you put too much soda ash in your pool, you have now taken calcium carbonate out of solution because of an LSI violation. It is now in suspension and turns white and clouds up your pool. Makes sense. Big difference between being in suspension of being and solution, truly, TDS is invisible. It does not actually create cloudy water. It does impact your LSI.
Eric [00:12:51] So in my opinion and Gerard, speak to yourself on your opinion. I don't know why we have these arbitrary numbers of fifteen hundred parts per million TDS. I haven't found much evidence to that. And here's my case. [00:13:04]If you don't have a salt pool, whatever your tap water is, plus fifteen hundred is probably going to be less than two thousand or three thousand. [7.3s] But if you have a salt pool, will you just add fifteen hundred on top of the salt number and now you're at four thousand or five. Why did we have the limit on the low end anyway?
Jared [00:13:21] Well, I agree. I mean, I think it's also in the same frame of mind when people say, I have old pool water. My pool has been here for five years, six years, 10 years, however long it may be. And they say they need to drain it every so often. And I wouldn't necessarily disagree with that sentiment. But as long as you're diluting, displacing, back, washing, whatever it may be, you're refilling it with fresh water and you're getting that, "old water" out of the pool. So therefore, your level should regulate out over time unless you're abusing things that you're putting in. If you're using two or three gallons of bleach at a time versus a half a gallon or you're adding, you know, way too much acid or way too much calcium or way too much bicarb at a time. These are going to artificially cause your total dissolved solid level to increase a lot faster than they normally should.
Eric [00:14:16] and then evaporation.
Jared [00:14:17] Absolutely.
Eric [00:14:18] Evaporation and [00:14:19]accumulation. In a typical outdoor pool, depending on your climate, you're going to evaporate about the volume of your pool in a year. [6.7s] Now, that really only applies to pools that are open all year. You're not going to have that in Connecticut, but you will have that in Houston. You will have that in Florida. You'll definitely have it in Southern California and Arizona because the temperature has such a much lower relative humidity, it'll evaporate water faster. When you do that, you accumulate these TDS or these dissolved solids much faster.
Jared [00:14:49] Well, I agree, it's part of the equation for water balancing. And, you know, like you're saying, TDS does not, quote unquote cause cloudy water. Well, it's just one piece of the puzzle. Just like when we get phone calls all the time - I know you do, "Hey, I'm an add your chemical and it's going to fix my pool." Whoa, whoa, whoa. If you have bad circulation and bad filtration, other things that we don't know about, it cannot be fixed with just adding a magic chemical. That's not how it works. Just like TDS is one piece of the equation for having clear clean water to work with.
Eric [00:15:26] Well, any way you look at it, having these limitations based on just total dissolved solids is kind of arbitrary. But there is a reason to be concerned with high numbers. And I'll explain. [00:15:39]If you're cyanuric acid gets too high, it's time to dilute water. [4.1s] If your calcium hardness gets too high and by the way, too high is subjective to where you are. Don't freak out if you have 500 calcium hardness, OK? Because especially in like Michigan or anywhere that your water is guaranteed to freeze in the winter, you're going to need that 500 for the winter anyway. But maybe you have tap water that's very hard, like eight hundred out of the tap. Chances are you're going to need to dilute that pool at some time and not because the TDS is high. It's because of the impact on the saturation index. And in the case of cyanuric acid, both the saturation index and chlorine efficiency. So those solids absolutely need to be maintained. Which brings us into our third point of how [00:16:25]the TDS actually lowers the LSI and makes water more aggressive. [3.2s]
Eric [00:16:30] So here's the nice thing. As you increase your calcium hardness or your alkalinity. Yes, TDS is going to go up in parts per million. But the impact that the calcium hardness and alkalinity have on raising the LSI is actually greater than the negative impact the TDS has per part per million. So if I go and add three hundred parts per million of calcium, yes, my TDS does go up 300 parts per million. But that doesn't mean I have the same negative that outpaces or equalizes with the positive that I just got from calcium hardness. It takes a lot more TDS to negate calcium hardness or alkalinity. And thank God for that, because if it was an equalizing thing, they wouldn't matter. They just wouldn't matter. So TDS it's a very small factor below two thousand. Hardly a difference at all in the LSI play around on the Orenda app. You can get it in the App Store or Google Play. It's just called Orenda. Play around with the TDS number. You'll see what I mean. But look at the difference between one hundred, which is the default baseline and three thousand. That's a that's a world of difference. So if you have a salt pool, this means you have to treat your pool differently than a normal chlorinated pool because your baseline is so much higher. You may have perfect LSI Balanced Water, seven five pH and three hundred calcium ninety alkalinity. Everything is just textbook perfect. But then you make it a salt pool with 50 cyanuric acid and it becomes aggressive. That's the reality is because it's not a normal pool. It is a salt pool. And you may have a small pool and you think, "wow. I have seven four pH and I, you know, it rises, but I maintain my pH, I have alkalinity right where it needs to be." You're probably struggling to keep that pH in place. You're probably having issues where your pool is actually etching every week in your pH spikes faster than it should. Of course, salt pools are supposed rise, but because that TDS was not accounted for in the LSI, you're not thinking about it. Go ahead Jared.
Jared [00:18:44] Which reminds me just as a caveat here. I know we've touched on it before. When you're entering the TDS number into our calculator, it's the total TDS, including the salt, not just the salinity level.
Eric [00:18:56] Good point. Yeah, good point on the Orenda app and says salt slash TDS or maybe it's TDS slash salt. The only reason we put salt in there is because a lot of people forget about salt. And actually there's two reasons. The other reason is if you need to know how much salt you need to add, that calculator is actually a dosing calculator, too. So it'll tell you in pounds or kilograms of salt that you actually need.
Jared [00:19:17] And a lot of times when customers call me doing startups, they'll pretty much ignore the TDS level when they're inputting the numbers on the tap water. And granted, there's not a ton of TDS in your tap water. There can be, but most likely there's not. But you still have to account for your TDS coming out of the tap and you're trying to figure out your LSI.
Eric [00:19:36] Certainly. It's usually under a thousand. So you're right. It is a small, small factor. You know, when the LSI was actually made before we made our calculator, it comes with a reference chart and anything under a thousand parts per million has some multiplier. And then it goes up a little bit if you're over a thousand. Well, we had to. We expanded that and we kind of went in by every hundred. And it gives you a clearer picture of what TDS actually does -
Jared [00:20:03] That's what... People call me all the time and say, "hey, I could use your calculator, but I'm getting your reading here and I'm getting completely different. LSI reading over here." And I understand that. And the reason being is a lot of times on the LSI formula, when you get to TDS, it says minus twelve point one or twelve point two, if you're over twelve hundred parts per million or under twelve hundred parts per million. Well, in reality, it's not that simple. Now granted it's for convenience and I understand that. But what we did is we definitely extrapolated that out to every hundred number. It gives its own factor for that TDS for the LSI. So that's why it's a little different. Just if you're wondering.
Eric [00:20:39] [00:20:39]So the higher your TDS, the lower your LSI. Keep that in mind. So salt pools have to be treated differently. Old pools, mature water has to be treated differently. The accumulation from evaporation is a huge contributor to it. Also, be wary of the chemicals you're using. Your chlorine is primary among them. Cal Hypo will leave behind calcium and other things like liquid chlorine leaves behind a lot of salt and other things. [25.1s] There are contaminants in liquid chlorine like iron and whatever else. Sometimes it depends on the chlorine. So just be aware. Algae sides always leave something behind. Mineral systems leave something behind. Fortunately for us, we have a policy at Orenda where we make chemicals that do not leave things behind. Long term. So like a phosphate remover removes phosphates, becomes inert and it physically gets removed by vacuuming or filtration, it's out. It doesn't actually contribute to TDS. Same thing with enzymes. When they do their job, they're gone.
Jared [00:21:35] So I'd say I'd say that's accurate. For the most part, there are some things that can accumulate in the water. But, man, we're talking such a small amount that it's negligible.
Eric [00:21:45] Well, the chelating agent would keep the metals in solution, but the chelating agent itself is not a dissolved solid. It was never actually solid. I looked into it. So I can say that it with confidence. But but anyways, that's immaterial. Just be aware that the older your water is, you're tending to have a higher TDS. [00:22:02]TDS meters are not that expensive. [1.2s] The really good ones might be. So if you're in the trade, it's probably worth investing in one, especially if you're doing startups or winterization. It's probably worth knowing. Anybody who deals with a salt pool should absolutely have a TDS meter. And if you're a homeowner, you can get them online for less than 30 bucks.
Jared [00:22:20] And not just that. Go to your local retailer too get a chemical panel every once in a while because you only need to check your TDS in our opinion every three or four weeks. Just like cyanuric acid or calcium levels. These aren't things you're checking every single day. They don't swing that much from day to day or even week to week unless something dramatic happened. So, get a baseline and check them every three to four weeks. And that's that's sufficient.
Eric [00:22:45] Which brings us into our final point. These numbers don't change much because the only way you can remove TDS. Is physically. The easiest one is dilution. Drain some water out. And I'm not talking about evaporation. I'm talking about dilution. So physically splash out in a commercial pool. But backwashing. That pulls water out with its minerals inside and discards it. You can do drain offs. You can take a pump. You can drop it down six inches or whatever it is, and refill from the tap. Draining in diluting is the most efficient way to reduce your seaway. And the other one is it is mechanically so like reverse osmosis filtration. That's a lot more expensive. But in drought stricken areas, it may be your only option.
Jared [00:23:29] Which, which and areas that open and closed pools down, they get the benefit of dropping their water down when they close a pool and then they get rain and snow usually and they get dilution from that. So it's it's a lot easier to maintain a lower TDS or Cyanuric level. And climates that drain and drain their pools down every year.So that's it. That's definitely a benefit and definitely a lot harder to do it in a Texas or Southern California or Arizona or Florida, where we do not close pools. So it's tough.
Eric [00:24:01] Yeah. Winterization you'll drop down a foot or two to get below the return. And let's blow out the lines. Then you get Mother Nature putting pure distilled water back into that pool. Rain or snow? That's distilled water. There's no minerals in it. There's no TDS in rain, OK, because it evaporated. It condensed up in the sky and it came down. So you will get the [00:24:21]dilution, which in closing is a main reason why if your pool needs to be winterized, you need to have an LSI strategy. You have to have more than you might think of calcium hardness and alkalinity in the winter [11.9s] because it will get diluted with distilled water. And that number will go down over the course of the winter. And you have to be able to maintain LSI balance. So quick wrap up here and then we'll close this episode out. I think we move through it pretty nicely.
Eric [00:24:48] [00:24:48]Total dissolved solids is anything that is truly dissolved. Not what's in suspension, but dissolved in your water. The biggest contributors are minerals and metals and salts. So a lot of that has to do with the chlorine you use. And of course, if you have a salt chlorine pool, you actually added the salt yourself. But it also includes cyanuric acid, alkalinity and other other things that you might not think about. But they're typically a lot smaller and less important. [30.1s] TDS limits, based on the book we find pretty arbitrary. But there are reasons to keep TDS in line. Mainly the Langelier saturation index, the LSI. So when it's time to drain, it's not necessarily because the TDS is too high. It's actually because maybe your cyanuric acid is too high or your calcium hardness is too high and you're having trouble maintaining LSI balance or chlorine efficiency. If that's the case, yes, it's time to drain and dilute because draining and diluting or physically removing TDS is the only way you can get it out. There's no chemical that goes after these things and removes them. You have to physically remove water and dilute it down or use reverse osmosis.
Jared [00:26:03] I say there's some that might flocking it will take TDS out of the water chemically. But you're still having to vacuuming it out and removing it at some point.
Eric [00:26:13] You're right. You could throw soda ash and precipitate calcium carbonate, vacuum that out. But that's small potatoes. When because what does that do for salt? It doesn't take salt out.
Jared [00:26:23] Like I said, if you're trying to flock something down, you can flock solids out of the pool. But it's a pretty big pain, which it can be done. So it is an option as well.
Eric [00:26:32] Yeah. Yeah. We'd probably take a lot of it. But in any event, that's total dissolved solids as it pertains to the LSI. I'm Eric Knight, your host for the Rule Your Pool podcast. As always, Gerard, thank you for being with us today.
Jared [00:26:47] My pleasure.
Eric [00:26:48] And if you have any questions, you can put them in the notes below or this will also be on YouTube. Comment below or contact us. Thanks so much for your time, everyone.
OUTRO [00:26:57] Thank you for listening to Rule Your Pool, a podcast by Orenda Technologies. For more information on what we discussed 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 chemicals wasting money. I'll see you next episode.