Understanding Chlorine Use in a Float Tank – DSP 174

This is another one of those questions that seems simple but as soon as Graham and Ashkahn start explaining a few things, you realize that there’s a lot of complicated information in the background. A “SSBASAGAASEAFTYRTTALOCIITB”, if you will.

The guys take this opportunity to deep dive on the complex conversation of chlorine and why it’s problematic for the float industry, along with several  caveats of the benefits and usefulness of it as a disinfectant.

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Transcription of this episode… (in case you prefer reading)

Graham: And we have a question that we’ll be answering, which is, “working with chlorine in a float tank, question mark?”

Ashkahn: Okay, a semi-question. I’ll give them the question mark. They got that part.

Graham: Yeah, but I could kind of tell their intonation was going up at the end, too, just from how they were typing that in. So full sentence. Ehhh.

Ashkahn: Okay. Working with chlorine in a float tank, question mark.

Graham: And not working against chlorine, which is an important distinction there.

Ashkahn: So I mean, this is big. This a big thing. In the float industry, people are constantly like-

Graham: For such a small question, it has a very big-

Ashkahn: -This is one of the biggest points of contention between the float industry and health departments. And there’s all sorts of stuff like that that we can talk about. But I’m assuming, in the scope of this question, you’re using chlorine, whether it’s because you want to or whether it’s because the health department is making you. So at the point that you are using chlorine, what do you do? How do you use it?

Graham: Yeah. What do you do? So we’ve used bromine before in our float tanks when we were first opening up. And right now, we use UV/hydrogen peroxide. So a lot of our knowledge of chlorine and its use in float tanks comes from external experience, consulting with centers who do use it, talking to health departments. But as far as using it in our own tanks specifically, that’s something that we haven’t done in the past. Just as a disclaimer.

Ashkahn: Yeah, yeah. So there’s a few different ways of getting chlorine into your float tank. Some people use what’s just called a chlorinator or brominator. It’s just this little device that connects to the plumbing of your filtration system. And you’ll get little tablets or small kind of pucks of chlorine mixed with some other stuff that you’ll put in there. And the water will go through and dissolve a little bit of it every time you run your filtration system. And that’ll be the way the chlorine is kind of slowly being introduced into your system. So that’s kind of one method.

Graham: It’s pretty common, too. [crosstalk 00:02:45].

Ashkahn: That’s pretty common. I also see a lot of liquid chlorine when people are using chlorine. So they make chlorine in liquid form. Again, usually there’s a few different types of chlorine that you can choose from. And that’ll either be automatically injected into the float tank, again, probably connected to some portion of the piping or something like that. They just make these little, tiny pumps called peristaltic pumps that just kind of are usually used as auto-dosers in kind of this sort of context. So same thing: you’ll run your pump, and it’ll just squirt a little bit of liquid chlorine into the solution as it’s going through. Sometimes people even hand-dose liquid chlorine, which isn’t, I think, quite as nice. Just be careful.

Graham: Yeah. Before, I’ve seen even hand-dosing a powdered chlorine as well.

Ashkahn: Yeah. So that’s the other type that you’ll see people do is powdered chlorine. There’s different powdered products and that’s almost always is being hand-dosed into the system.

And then there is also gas chlorine, which-

Graham: Is totally insane.

Ashkahn: Yeah. You’re never going to see that used on a float tank. You hardly even see them in the pool and spa world anymore. They’re kind of more old school. They’re huge. I mean, you’re talking-

Graham: We got to go on a tour of an area that had one. So we got to kind of check one out first-hand during one of our kind of aquatics conferences we attended.

Ashkahn: But these things are probably like the size of your entire lobby.

Graham: More like all your entire shop in some cases.

Ashkahn: And there’s an entire huge HVAC system that’s just as big that you need on top to be able to fully suck out any gas if something goes wrong. And you need to work with the Department of Defense to make sure that terrorists can’t come and take over your site. And you have to work with the city and the state to make sure you have an evacuation plan. I think you have to evacuate an eight-mile radius around your facility if something goes wrong. Basically, if something goes wrong, this chlorine gas, which is just going to kill people, just starts to flow out everywhere, which is real, real crazy.

Okay. Side story, side story. The chlorine gas is heavier than air. So it’ll actually start by sitting on the ground. So if you ever find yourself in a position where someone has breathed in chlorine gas and is unconscious or something, what you’re actually supposed to do is pick them up by their feet and hold them upside down so the chlorine gas will come out of their lungs and out of their mouth, which hopefully, you won’t ever find yourself in a position like that. But now you know, now you know.

Graham: Keep that visual in mind if you are thinking that the chlorine gas situation sounded kind of cool, or working with the Department of Defense or something.

Ashkahn: Yeah. So it’s not going to happen. You’re not going to use gas chlorine in a float tank. So you’re getting chlorine into the system. And at that point, when people are measuring kind of chlorine levels or when you see recommendations for ideal ranges and minimum/maximum ranges, things like that from health departments, usually what you’re measuring is something called free chlorine as opposed to combined chlorine. And so free chlorine is the chlorine that’s still active in your solution, ready to kill stuff. And once it kills stuff, it kind of connects with it, and then it becomes combined chlorine.

Graham: Which is how chlorine works as a disinfectant to begin with. It’s such an unstable compound there, that it wants to bond to just about anything, which then kind of has chlorine little molecule attached to it and becomes a weird, non-dangerous version of whatever it is is the basics of how the heck this is even working.

Ashkahn: Yeah. So chlorine and bromine are both on the same column of the periodic table, and I think they’re both short two electrons. And so they kind of very readily connect with other things. And once chlorine or bromine connect with stuff, they don’t do a very good job of continuing to kill things. So what you’re really measuring when you want to measure like, “Hey. How much chlorine’s in my system? Is it enough to keep people safe,” you’re measuring that free chlorine number, that number that’s telling you how much is available to still do its job as a disinfectant. And those numbers, those free chlorine numbers, the kind of first thing that comes into people’s head in the float industry when they think about chlorine and bromine is the kind of health issues related to them.

And typically, when people are concerned about that stuff, they’re not really concerned about the free chlorine; they’re more concerned about the combined chlorine and what results in the process of chlorine or bromine combining with things. Because these are all chemical reactions, and there can be hundreds, hundreds of different chemical reactions that happen when chlorine interacts with a whole host of various bacteria, when it interacts with the urea in your sweat, when it interacts with makeup or pharmaceutical-

Graham: And it’s all really complicated, and none of it makes any sense, not even to chemists. It’s beyond the level of human comprehension almost, the insane things that chemical reactions do.

Ashkahn: And some of these chemical reactions are inert. Or at least as far as we know, they’re inert. We don’t really think they have much harm to us. And some of them are things like chloroform. And other ones can cause long-term respiratory damage.

Graham: Usually the trichloramines is the ones that people are sort of worried about coming off of combined chlorines specifically.

Ashkahn: Yeah. So people are often concerned about things that become gaseous. It seems like the most harm comes when things kind of leave the water and turn into a gas. And there’s kind of the larger family of those called the trihalomethanes, which trichloramines is kind of the one that people usually quantify when they’re trying to see the impacts of air quality. And these things, they’re not good for you. Some of them might be fine, but other ones are definitely known to lead to issues. I mean, there’s something just colloquially called, I think, lifeguard lung or swimmer’s lung just because they know the people who are around pools, especially indoor pools, for long periods of time will develop these kind of respiratory issues.

Graham: And there have been more and more studies coming out, especially in recent years, just kind of showing that impact on things like lifeguards and stuff like that, actually having them wear little sensors on their shirts to measure the different levels of the trichloramines coming off of pools. So it’s been a topic of conversation, not just in the float world, but kind of the pool world at large. And it seems like it’s becoming a bigger and bigger conversation, even over the last five years that we’ve been paying really intent attention on it.

Ashkahn: Yeah. And some of these things are even kind of carcinogens and stuff like that. And when you hear about it in the US at least, you hear a lot more conversations about indoor pools than outdoor pools because outdoor pools have the benefit of the wind coming and blowing things away. And they still have done studies on outdoor pools, and they’ve still found levels that are kind of above the levels that we think are maybe appropriate. But people kind of debate back and forth, but almost everyone I’ve talked to seems to think that there’s an issue with air quality and indoor pools here. And that we need to do some stuff to be able to deal with it.

And so the concern in the float industry comes from the fact that float tanks are much smaller than an indoor pool is. And you’re basically in not a very large container. And there’s not a lot of active airflow in there because you don’t want to feel big gusts of breeze across your body while you’re floating.

Graham: And your nose and mouth are just right above the surface of the water, which is where a lot of these things like to hang out, too.

Ashkahn: So that’s the concern, that there’s kind of air quality issues that we know happen in swimming pools and that might be of especially high concern in a float tank setting. I usually like to also maybe balance this out a little bit because no one, as far as I know, there’s not huge amounts of data on people actually measuring levels of tricholoramines or trihalomethanes inside of a chlorinated float tank to say, “Okay. We tested it. It’s definitely above these levels.”

Graham: Which if you’re listening and you know of some research, certainly shoot it along our way.

Ashkahn: But it should be noted that there are arguments to be made for why those trihalomethanes or things in the air might be lower in concentrations that they would be in a pool or spa to begin with. One thing is these things are a result of chlorine combining with things and interacting with different stuff, and the different stuff that people bring into pools, and the different things that end up in pools like from whatever’s in the air, and just being a much more open environment. So we have a lot less of that in a float tank.

A big one is people showering. When we go to these conferences and we hear people discussing what to do about indoor air quality in pools, almost always what trumps technological improvements or whatever regulations and stuff like that, just getting people to shower before they go into a pool, they all agree, would make probably the biggest single difference.

Graham: And it’s functionally, for them, really, really hard to make that happen. The stats on people actually showering before getting into a pool are pretty abysmal in a public setting.

Ashkahn: But we have that with float tanks. So the fact that people are showering is probably introducing less stuff into our float tanks that would, at the end of the process, result in combined chlorine disinfectant byproducts, trihalomethanes, all that sort of stuff.

Another one is the agitation of the liquid, the stuff usually that goes from liquid form to gas form as a result of agitation. So people swimming laps, people splashing, stuff like that in pools is what can encourage the process and speed up the process of those air levels getting higher. So we have some agitation of the water when you run the filtration system and stuff like that, but while people are actually-

Graham: You get in there and vigorously splash around.

Ashkahn: Yeah, yeah. I start just by kicking the water in the float tank when I get in. But in general, people are lying there. And so during the course of a float, you’re not doing a bunch that agitates the water that would encourage that kind of gaseous production of those different elements.

Graham: And it also means you’re not sweating,  your sweat can definitely again, with medications you’re taking, or sunscreen, or anything like that actually get into the water and start combining with chlorine as well.

Ashkahn: People peeing in the pool, that is a result of it. I don’t think we really have people peeing in float tanks. And UV helps. There’s a lot of complicated chemistry that goes into that as well. It turns out UV and chlorine also creates more disinfectant byproducts when UV hits these various chemical molecules, and reactions, and stuff that chlorine’s been forming. And it also seems like UV helps break down and destroy some of those disinfectant byproducts. And as best as I can tell right now from the people who I’ve seen give presentations on this, the net effect is positive. It destroys more stuff than it creates and has an overall benefit to your system.

So again, it gets real, real complicated. And it gets to the point where we’re really just at the edge of what your health inspectors, or regulators, or any of those people actually know about how any of this stuff works, too.

Graham: Yeah. For sure. And just as far as other things that make it maybe a little safer for not having a ton of stuff in there that chlorine is combining with to form these disinfection byproducts is also just a lack of kids. That’s a huge one whenever you’re talking about what’s getting into public swimming pools and stuff like that is they have to put up with younger kids. And sometimes, they’re even in diapers and all kinds of crazy stuff that, as a float tank center owner, we just don’t deal with, or at least don’t deal with on any kind of regular basis like public pools do.

Ashkahn: So at this point, we’ve really said very little that’s practical in any way. But all of this is to give you the context of when you’re using chlorine, if you’re using in a float tank, one of the big things you’ll want to do is try to reduce this production of combined chlorines, disinfectant byproducts, trihalomethanes. These are the things that to use chlorine well, you’re trying to have as low of numbers on these things as possible. And so a big part of that just goes into good operations, really making sure people are showering beforehand, and your showers are in the float rooms, all that. You’re making sure that you’re providing a clean environment. All that sort of stuff leads to a lower concern of health risks when it comes to how you’re using chlorine inside of a float system.

What you do with chlorine is you do something called shocking the water. And so when you build up these levels of combined chlorine, you can shock the system either using more chlorine, and there’s an equation that you can find online and plug it into to figure out kind of how that stuff works. Or they make these things called non-chlorine shock which you can use that basically what it’s trying to do is break down those combined chlorines and kind of free up the chlorine again. So when I hear of float centers using chlorine or bromine, they’re usually shocking, I’ve heard, anywhere from once a day to once a week.

And there’s some weird stuff that comes with that. If you have a lot of heavy metals in your water, which if you’re not using any sort of filtration when you’re filling your float tank, anything from an RV filter to full kind of water filtration for your building, sometimes shocking the system can encourage those metals to oxidize or come out from what they’re otherwise combined to. And your water will turn colors like bright orange if you have a lot of iron in your water or something like that. So that can be something you want to keep an eye on when you’re shocking.

Graham: Yeah. We see it more often kind of reported when people are using bromine and non-chlorine shock because, especially the potassium monopersulfate is kind of the double whammy that almost always causes trouble for people. But we have seen some similar things even with different heavy metals, too, with the use of chlorine in shock.

Ashkahn: So yeah. Making sure to filter the water going into the float tank, and there’s also vitamin C powder and ascorbic acid, can help undo those crazy colors if they do happen in your system. So that’s a good thing to keep an eye on. Another thing you might want to consider is trying to maintain a slightly lower level of chlorine. The ideal range for pools might be a little higher than we actually want in a float tank because they have to have a lot of buffer to deal with bus full of school children, I mean, right? Diving into their pools?

Graham: Which we don’t have as much in float tank centers.

Ashkahn: Germany has regulations where they set their chlorine levels all the way down to half a part per million, which is lower than you see anywhere that I know of in the US. And it’s combined with a lot of other things. People shower before they go in. They have a lower pH which can make the chlorine more effective. There’s a lot of stuff like that that they do to be able to make it so that they can use a lower amount of chlorine for the same amount of effectiveness.

Graham: And the argument there to make with your health department, if they are giving you pushback on requiring the exact same parts per million as for a public pool, really is just that it’s a totally controlled bather load and that you do get to run a filter between every person. There’s a certain amount of buffer that public pools want, like Ashkahn said, for not just a busload of people, but even being in there just next to a stranger at all. So pointing out those differences sometimes helps that conversation go a little smoother.

Ashkahn: Yeah. And it does come with the other variables. You can’t just drop your chlorine and stay in a higher pH range and stuff like that. It won’t be as effective as being in the higher parts per millions.

Graham: Another one, I think, that’s really important to pay attention to, which the kind of background might have made a little obvious, but just the actual ventilation going into your float tanks. How are you getting your air exchanges? And making sure that you’re putting some serious thought into a system that will evacuate some of the air from just above the kind of water line there, or at least keep it moving. And it’s a much more difficult problem than you might think because if you do have active airflow that you can feel, or sometimes even that you can’t but that is present, you’ll get salt crystallizing on your belly. It can really make some of your floaters cold. So finding that balance of making sure that you feel confident in the amount of air that you’re moving in the space to not just have a lot of these disinfection byproducts hanging out above the surface of the water but that still gives a comfortable float. It’s just one of those things when you’re using a chlorine system that will take some time to totally balance and get right but definitely needs your attention.

Ashkahn: I often recommend people have a variable speed ventilation fan in the room so that they can be venting kind of all the time while the float is running, but then during those transition times, they can bump it up to a higher speed that makes noise. But it doesn’t matter; no one’s in the float tank at that time. And you can get, at least for that period of time between floaters, really decent air exchange going in your float room and your float tank.

Graham: Yeah, yeah. For sure.

Ashkahn: So now comes the bad news, which is that everything we’ve said so far is assuming that you can actually kind of functionally use chlorine and measure things. And that’s where things get a little bit tricky as far as I’m concerned. Whether chlorine levels can be accurately measured in a float tank, to me, is something that’s up for debate. We’re pretty hard nosed about it. Because these test kits that people use rely on chemistry, chemical reactions, and because what we have in the float tank is significantly different than water. There’s 1,000 pounds of magnesium sulfate mixed into it. My perspective with any sort of chemical testing device in a float tank is kind of a guilty-until-proven-innocent approach. I just assume a test kit is not accurate until the manufacturer of that test kit has tested their thing in their own lab with our float tank water and come back and told us in some sort of official manner that, in fact, they are getting accurate results.

Graham: Yeah. And specifically not from the sales department. It’s amazing how if you’re talking to salespeople, they’re like, “It definitely works.”

Ashkahn: And not even them just saying it. People will just be like, “Yeah. I checked it and everything seems it should be fine.” Because the times we have had it tested, it does not seem to work accurately. So that’s not say this doesn’t exist. Some manufacturers, maybe they’ve talked to their test kit companies or something like that. But if you’re using a chlorine test kit, that’s what I would want to know, that it is, in fact, accurate because we know for sure there are some out there that are not accurate. So it’s definitely very easily possible that many, many chlorine test kits and bromine test kits are not giving you accurate results.

Graham: Which is more of our suspicion, I guess. Hence the guilty-until-proven-innocent. In our experience, it seems way easier to run across ones that give inaccurate readings. We have no data on this, but I personally would venture to say that my theory is the bulk of them are not actually giving you accurate readings, especially for chlorine and bromine.

Ashkahn: Yeah. So we don’t know everything that’s out there, but keep that in mind. Don’t just trust something unless you have some sort of validation that it works.

Graham: And don’t assume that if you’re spending more money on it, now you’re getting a nice $100 spectrometer kind of test kit, that it will perform any better than just test strips or something like that. It being more advanced does not mean that our crazy difference in chemistry will still make it anything but just kind of giving you a reading you can’t trust.

Ashkahn: The other difficulty comes with kind of measuring everything else. So chlorine’s efficacy and bromine are based off of pH. The more acidic something is, the better the chlorine and bromine can usually do at killing stuff. And so you have to regulate and maintain your pH within a certain range to make sure that your chlorine and bromine are working effectively. And same sort of deal, I’m not totally convinced measuring pH in a float tank is that easy. I, again, have gotten things back from test kit manufacturers saying when they tested it in their labs, they were not getting accurate results. I’d put it in that same camp. I’d want someone to give me actual confirmation that I’m getting the right pH range.

And then alkalinity is what you use to stabilize pH, and I’m almost certain there’s no accurate alkalinity meter out there. That’s the one that I always get the strongest reply back on of-

Graham: “What have you done to our test kits,” is usually what they write back.

Ashkahn: We sent a sample of salt water to two of the biggest test kit manufacturers here in the US. And they both came back and said, after testing it, they don’t think they have a single test kit that they make that would accurately work for measuring alkalinity for us. And so that kind of really creates a very pragmatic difficulty with chlorine and bromine. You can’t really measure the chlorine and bromine very well. You can’t measure the pH very well, which makes the chlorine and bromine effective. And you can’t measure the alkalinity very well that makes the pH stable, that makes the chlorine and bromine effective. So if you are talking to a health department and that’s kind of the direction why you’re looking at this chlorine and bromine. That would be my first question for a health department. I would be like, “Can you provide me with a test kit that is accurate? Can you give me a test kit that you know to be accurate for me to use in these systems?”

Graham: And that’s a big question for them to try and answer, so I don’t even know exactly how they’d go about doing that. And I think most often, they just want to use the test kits they’ve always been using. So it’s a little bit of education on your part that you need to do when you’re going into these conversations to really point out that their test kits are likely not going to give the same accurate results that they’re used to getting. And we have a good resource on the Float Tank Solutions website, too. If you download the health department essentials, it covers a lot of the basics of this stuff that we’re talking about. How to talk to health departments about things like using chlorine. And it contains a study in there which is the only one that I know of at least for testing the efficacy of different chlorine test kits. And it just used a couple different test strips and, I think, one DPD tablet kind of method.

But it came back saying other than with dilution calculations and then doing an adjustment ratio, there’s nothing that they found that just, out of the bottle or out of the box, was giving them accurate measurements.

Ashkahn: Yeah. Which I guess it’s worth noting they did get it to work with dilution, but the practicality of doing that, when you’re using chlorine, people often want you to test your chlorine levels every two hours, three hours, four hours, something like that. And this would involve taking a sample of your water I think they had to dilute it down to 1 to 1,000 or something like that, some crazy dilution to be able to test it accurately. So it’s a very cumbersome process to be able to do something like that.

Graham: And again, you can grab that documentation, and that might be a nice document to show to your health department just to get them on the same page and realize that you’re not just making this stuff up. And in fact, even in laboratory settings, they can’t get test strips or kind of regular chlorine tests to work how you’d expect.

Ashkahn: Yeah. And I guess the last thing I want to say is chlorine is good at killing stuff. We shouldn’t lose sight of the fact that it can kill things in seconds: E. coli, Pseudomonas, these things that we’re concerned about people getting sick with. It is very effective at killing those. It’s not very effective at killing a few things, namely Cryptosporidium and Giardia, which is why a lot of pools have UV and other things because there’s a few things out there that chlorine just does not do a very good job with. But the reason it’s used all over the place is because it kills things, and it kills things quickly.

Graham: And it’s well studied to chemists.

Ashkahn: And it’s very well studied. I mean, people have been using chlorine and bromine in pools for longer than- Not thousands of years, but like 150 years or something like that.

Graham: Just round it up to the nearest thousand. Yeah. And I was just going to say with great power comes great responsibility there. It is very powerful, but there are-

Ashkahn: We should end every episode with that, I think.

Graham: Give a little Uncle Ben maybe on our album art might pop up there. Anything else about chlorine in float tanks?

Ashkahn: It’s complicated. It really is super complicated stuff. We’ve spent years trying to learn this, and we still realize that we are wrong about something we thought for years. And that’s because everyone is like that. There’s just new information coming out about how chlorine works, and how it responds to UV, and how it mixes with other things.

Graham: Yeah. Separate even from float tanks. Just in general, this is how, I mean, science works. And specifically in the aquatics industry is you kind of make your best guesses and a lot times, you get more knowledge. Those are 100% wrong. So who knows exactly how accurate what we’re saying right now-  

Ashkahn: Yeah. These are just our best guesses.  

Graham: -ultimately will be. But yeah, it’s the best information that we have right now.

Ashkahn: So good luck.

Graham: And if you have more questions, definitely shoot them our way. It’s floattanksolutions.com/podcast is where you want to go to do that.

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