Surprising Pool Chemical Reactions Every Pool Pro Should Know

Pool chemistry gets called “simple” right up until a clear pool turns milky, a filter pressure gauge shoots up, or a perfectly good cartridge comes out feeling like it turned to stone. We move fast through the most common chemical misconceptions we see in the pool industry and explain the real reactions underneath, so you can prevent damage instead of explaining it after the fact.

We start with cyanuric acid (CYA) and the assumption that stabilizer only drops when you drain and refill. There’s more to the story: under certain conditions, bacteria can convert cyanuric acid into ammonia, and your CYA can crash, especially after winter.  From there we hit calcium chloride and why it heats up aggressively, plus the practical rule that saves you from a cloud-out: don’t stack calcium additions right next to pH up or alkalinity increaser and accidentally spike the LSI.

On acid washing, we cover a simple basin tactic with soda ash that can prevent an ugly deep-end “burn ring,” and a small step to reduce rust staining from a submersible pump. We also clarify what phosphate removers really do, how lanthanum phosphate fallout clouds water, and why filter cleaning is part of the process. We close with the most important safety warning of all: never mix trichlor with cal hypo, especially in confined spaces like feeders or skimmers.

• cyanuric acid not always only lowered by draining, bacterial conversion to ammonia as a real cause of CYA loss
• calcium chloride as an exothermic product, burn risk and why timing matters
• avoiding LSI spikes by separating calcium additions from pH and alkalinity adjustments
• chlorine wash best practices, dilution and thorough rinsing to prevent alkaline film
• how poor rinsing after a chlorine wash can destroy DE grids and cartridge pleats
• acid wash basin protection, using a trichlor bucket lid under the pump to reduce rust staining
• preventing a deep-end plaster burn ring by loading the basin with soda ash
• phosphate removers as lanthanum chemistry, expected clouding, fallout, and filter pressure rise
• trichlor

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Transcript

Welcome And Chemical Speed Round

SPEAKER_00 1:02

Hey, welcome to the Pool Game Podcast Show. In this episode, I'm gonna go over some common chemical misconceptions, kind of like a speed round where I'm gonna just touch on one and give you some information on it. I think you'll find this very informational and helpful with the chemicals we use here in the pool industry. Are you a pool service pro looking to take your business to the next level? Join the pool guy coaching program. Get expert advice, business tips, exclusive content, and get direct support from me. I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at swimmingpoollearning.com. I'll start with this one here. Cyaneric acid. We are told that it doesn't evaporate out of the pool, and you have to do a partial drain and refill. There are some things that, of course, they sell in the market that are supposed to lower the chlorine level without you draining the pool. But I find that they're not really cost effective because you have to pay quite a bit of money for these products. They have a finite kind of range to work in, water temperature, chlorine level, things like that. And by the time you finish putting these products in and spending the money for them, you might as well have just partially drained the pool, refilled it, and paid a little extra water bill, in my opinion, in most areas. That's still less expensive. But did you know that cyaneric acid can actually disappear from your pool or kind of drop in the winter time? And you may be wondering, well, it's probably because a lot of the rain diluted it. I mean there's some dilution there, I'll grant that. But the cyaneric acid can be converted to ammonia by a certain bacteria that gets into the pool, and sometimes it can actually zero out the entire pool. And this is pretty interesting. It's not an algae, it's basically a bacteria. And this has been documented from a lot of people, especially some guys in my group that noticed that the cyaneric acid level did deteriorate. So I would say that we probably have to add one more thing to cyanaric acid. It's not entirely accurate to say that the only way to lower cyaneric acid in the pool is to partially drain or drain the entire pool out. There is some evidence that a bacteria can deteriorate it. In fact, the bioactive does use that is as a primary part of their product that destroys the chlorine level in the pool. And that product does work. However, like I mentioned, there's a really fine range, the temperature of the water, the chlorine needs to be at zero basically, otherwise it kills the bacteria and it won't destroy the won't lower the cyaneric acid level. So, yes, there's another way cyaneric acid lowers in the pool, and it's not just by draining the water. If you want to raise the calcium level in a pool, of course, you're going to use calcium chloride, but then you know that it gets really hot. It's a product that really gets hot. It's an exothermic reaction. If you were to put some of this in a bucket and add water to it, it actually gets even hot enough to burn you with a splash out of the bucket. And of course, the rule is always add water to the bucket and then the chemical into the water. And you can add this directly into the pool skimmer as well. And you want to be really cautious with this because it has a reaction to any kind of alkalinity or pH up chemical. And this kind of happens unconsciously when you're trying to balance a new pool startup, or if you're trying to balance the pool where you get there, calcium hardness is like below 100, and then your pH and alkalinity are really low as well. Let's say the alkalinity is at 40 and the pH is at you know 6.8, and you want to, of course, adjust these things. I caution you to adjust the pH and alkalinity first separately and then wait, of course, for the following visit to do the calcium chloride. Because if you were to add the calcium chloride to the pool and then the soda ash or the baking soda to raise the alkalinity or the soda ash to raise the pH, what happens is that they kind of it kind of causes the LSI to spike, which causes some fallout. And what's gonna happen is that you're gonna, of course, the pool's gonna get cloudy right away, and then you're going to clog up the filter media, it's gonna leave some residue also on the surface. It'll pretty much cause a mess that takes a very long time to clean up and rectify. A lot of sources will say four to six hours. You can add it after. If you add the calcium chloride, you can add the pH or alkalinity up four to six hours afterwards. I'd caution you just to wait, you know, a couple days just to make sure there's not going to be any kind of reaction. I'm pretty paranoid about this, and you want to make sure that you don't have this reaction yourself because once you do, it's a it's a big mess. Here's one that also can be very messy. You don't hear this talked about very often, but a lot of pool companies will do a chlorine wash where they drain the pool and they take liquid chlorine and they wash the surface of the pool with it. Basically, they use a flower pot or a spray bottle and they spray it on there. This is done if the pool has a lot of black algae or a lot of algae and you want to treat it and you want the pool, of course, to come back and be white again. Barring an acid wash, of course, this is a pretty good method to clean the pool up and get all the organic staining and algae off the pool surface. The problem is that if you use pure liquid chlorine, which of course is not pure, it's a percentage. You know, let's say you're using the Hasa is 12.5%. If you were to spray this on the pool surface and then hose it off, but you hose it off poorly, you don't really give it a full hose off, and some of the residue stays on the pool surface. The sun is hitting it at this point, and it's kind of baking it. Now, what happens here is that there there is a chemical reaction that happens when the sun UV rays and it dries on there, and there's a caustic soda aspect of the liquid chlorine. So it leaves a film on the plaster that you don't see. And this film is a really high alkaline salt that gets on the surface at this point. So if you do a chlorine wash, I recommend diluting the liquid chlorine, of course, with some water so you don't have the pure quote unquote pure liquid chlorine on the surface. And you want to rinse this really well, especially if you're going to do an acid wash following this, you know, later on in the day or later on after you do the chlorine wash, because you don't want, of course, the acid and chlorine residue to mix together. But if you're just doing a chlorine wash by itself and you rinse it poorly, this will be a side effect when you refill the pool. And I've seen this happen. If you have a D filter, the grids will turn into like cement. If you have a cartridge filter, the pleats will also turn into like a cement-like substance from all of this high alkalinity salt or the caustic soda effect getting into the equipment, and it's gonna leave it leave a residue on the surface as well to make it really rough. But the real damage will be the filter elements. You're going to have to replace the cartridges and the DE grids. There's no other way I can say it, but it's kind of like if you had Medusa's head, it you put it towards the cartridge filter, and it turned everything inside there to stone. And that's basically what's going to happen to the elements in there. There's really no way to clean it, and you're just gonna have to throw it away. It's one of those things where you don't hear about it often, but it does happen, and I've heard it happen a couple times now, and people don't understand what happened to the filter, why is everything turned into a stone? It's because of this reaction with after the chlorine wash. So I would say dilute the chlorine if you're gonna do a chlorine wash, and if you don't dilute it for whatever reason, really really hose off that pool, so it's kind of like it's been diluted after the fact. Here's a caution for acid washing a pool, and this of course can be a big problem after the acid wash. You want to make sure you listen carefully here and don't make this mistake when you're doing an acid wash. I thought that was a great placement for liability because this could cause a liability issue after an acid wash. So, one thing that you want to be sure of, and this is really logical, and you can analyze this or come to the conclusion very quickly that this would happen if you don't follow this step. There are two things you need to do in the acid wash basin. So this is the deep end of the pool, usually by the main drain. When you're pouring the acid on the walls and hosing it off, all the acid will go down to your submersible pump that's gonna be right there in the basin of the pool or the deep end or the deepest part of the pool, and all this acid water is going to be taken out by the submersible pump. So, two things you need to do. Number one, if you're using a submersible pump that has a metal bottom or any metal on the bottom, go ahead and take a trichlor bucket lid. You have probably plenty of these everywhere, and put the submersible pump on top of the trichlor bucket lid. You can tape it there with duct tape too to make sure that it stays on there. And this will prevent the acid from causing any kind of rust stains when it's hitting the submersible pump. Usually it doesn't happen if it's newer, but as it gets older, there may be some possibility of a rust stain. It kind of defeats the purpose of the acid wash if you leave a rust stain on the bottom from the submersible pump. So put it on a chlorinator lid, duct tape it on there. A lot of guys do that when they do the initial drain as well. And this is a good safety measure to prevent that from happening. But the biggest issue that you're gonna find with the basin in the acid wash is if you don't load it with a lot of soda ash. I like putting liberals amounts of soda ash in the basin. This will, of course, cause the acid to become more base and less acidic. If you don't put any soda ash in the basin and you're hosing off all this acid down into the basin where the submersible pump is, the acid water actually sits there a lot longer than it does on the walls of the pool. Let's say you're doing this and you spend half an hour doing all the acid washing on the walls. That water in the basin is there for like half an hour basically, highly acidic if you don't have the soda ash in there. And the thing that happens is that once you're done with the acid wash, you may see see a ring in the deep end, maybe a two feet or three feet ring in diameter. And this is from the acid kind of burning the plaster right there. And this is the ring will often look much lighter in color if it's a dark-colored pool, and it may look like a burn mark in a white plaster pool. So this ring is very visible once you fill the pool up, and this is where the water sat in the basin where you didn't have a base product like soda ash in there to raise that pH up. So you'll probably have to redrain the pool and sand that area to get it to kind of match the same color as the rest of the plaster, and it's extremely avoidable if you go ahead and make sure that you have the soda ash in the bottom. This also is the same with light fixtures. A lot of people remove the light fixtures when they do the acid wash and leave them dangling because some of the metal, some of the rust could come out when you're doing the acid wash and leave a streak by the light fixture. I just kind of splashed a little bit of soda ash on a light fixture so that when the acid hits that area it becomes high in pH and doesn't really cause that rust stain. But you can certainly remove the fixture and let it dangle into the pool while you do the acid wash to prevent any kind of metal streaking at the light fixture as well. This is one that I hear all the time, and this is on phosphorate removers, and it was one of those things where a lot of the old school pool guys never really believed in it. However, we know now that there's a lot of orthophosphate being pumped into the pools. There's a lot of phosphates and a lot of products, which causes phosphates to enter the pool, and of course, phosphates are a food source for algae algae. They're actually just one food source for algae, so there's actually more than one food source. But if you use a phosphate remover, you're actually removing that food source, which in most cases will stop the algae from growing in the pool. Now, phosphate removers are not an algae side, so you have to, of course, clear up the algae first, and then of course you're going to have the phosphate, the the phosphate remover will remove that food source from the algae and prevent it from coming back. And that's why once you treat a pool for high phosphates, the nice thing is that you don't have to worry about algae, and you can put a maintenance dose in that pool every week that'll prevent any algae from growing. Because that phosphate is a really popular food source for algae, and it's something that once you remove it, the algae typically won't come back in that pool. Now, there is something that happens when you put too much phosphate remover in the pool, and even if you are putting the regular amount in there, you're gonna see some fallout. The pool probably will get cloudy, and it's not the algae falling out or being killed by the phosphorylemover necessarily. The phosphoryl removers they use a chemical called lanthanum, and this kind of bonds with the orthophosphate in the water, causing lanthanum phosphate. And so this new compound is not soluble in water. This is why the filter pressure rises as well, and you have to do filter cleanings after doing a phosphate treatment because it is kind of like a dust that forms in the pool from this treatment. If you overdose the pool, you're going to get a lot of fallout. The higher phosphate levels will cause more fallout, and this will go into the filter. Typically, if you have a suction side cleaner, it'll pick it up on the bottom of the pool and bring it into the filter. Regardless, the cloudiness of the water will also go into the filter, and this causes the filter psi to rise in the pool. So, depending on how much phosphate is in the water, how much phosphate remover you put into the water determines how much of this fallout or this white dust that gets into the pool and into the filter. And typically, after doing a phosphate treatment, you're going to have to clean the pool filter because of the lithium phosphate that's in the pool after you add the phosphate remover. It's almost like a similar effect if you were to add aluminum sulfate or pool flock and everything drops to the bottom. Very similar reaction with the phosphate remover. Of course, I would be remiss if I didn't end this with the caution of mixing trichlor with calhypo. This can cause an explosion, it could cause injury, even a fatality. So you don't want to mix calhypo and trichlor together in any form, circumstance, or condition. Basically, when trichlor and calhypo are mixed together, they undergo a rapid chemical reaction. So anything that goes under a rapid chemical reaction, like an atomic bomb, basically, that's kind of how it actually works. There's a chemical reaction that splits the atom, which causes you know tremendous force being produced. It's pretty amazing if you read about the atomic bomb, how it works. But with trichlor and with cal hypo, this releases a highly unstable nitrogen tric trichloride gas. The grass, the gas, of course, is extremely volatile and it can easily detonate spontaneously, which is the explosive part of it. So if you've seen like on Facebook groups where someone shows a chlorinator that has exploded the trichlor chlorinator, when someone put calhypo tablets in there, that's the reaction you get from this gas itself. And if it's confined, that's of course what happens when you put it in a trichlor feeder, sometimes even in a skimmer with a lid on there. That's a confined area. If you have a trichlor tablet in the basket, you pour some some cal hypo in there with the pull-off, and you put the lid on that. That confined area, the gas is built up and it causes that explosion. So you never want to mix trichlor and calhypo together because you'll have an explosive reaction. And unfortunately, this happens all the time with the advent of calhypo tablets or people that put trichlor tablets in the skimmer basket. It's one of those things that is definitely avoidable, but it does happen, and you want to make sure you don't even use like a calhypo scoop and leave it somewhere where trichlor can touch it because that could cause a reaction as well. That's a lot of scary stuff to digest in one podcast, but I think it is effective to go over all this so that you kind of get you're kind of aware of chemical reactions as well as chemicals that could cause some liability issues for you out there on your pool route. If you're looking for other podcasts, you can find those by going to my website, swimmingpoollearning.com, clicking on the podcast icon on the banner. There'll be a drop down menu of 1900 podcasts for you there as well. And if you're interested in my coaching program, you can learn more at poolguidecoaching.com. Thanks for listening to this podcast. Have a rest of your week and God bless.