Is Copper a Friend or Foe in Your Pool? – Bob Lowry Explains

Copper promises a cleaner pool with less work, but the chemistry tells a different story. We walk through what copper really does well—suppressing algae at low levels—and where it falls short, especially on fast disinfection and heavy oxidation. If you have ever wondered why water looks clear but still isn’t truly safe, or why blond hair turns green after a weekend swim, this conversation connects the dots and gives you a plan you can trust.

We break down mineral and ionizer systems on the market, the narrow gap between effective copper dosing and staining, and why non-chlorine oxidizers struggle with complex sunscreen molecules. You’ll hear why the EPA still requires chlorine alongside ionizers, how low residuals collapse under bather load, and the simple, reliable workflow for killing algae with 25 ppm chlorine held for 24 hours. Then we go practical: how sequestrants work, why they degrade in sunlight and under shock, and how to remove metals instead of endlessly binding them.

For pools already battling stains, we outline a step-by-step in-water remediation: lift discoloration using ascorbic or citric acid, capture dissolved metals with skimmer media or a dedicated canister loop to speed removal, and only then resume strong chlorination. We also help you find the source—copper algaecides, acidic tablets in the skimmer, heater corrosion, high-velocity erosion, fill water, or even iron-bearing pebbles in new surfaces—and share the surprising fix for localized rust spots. 

• copper’s effect on algae and bacteria
• limits of ionizers and the need for oxidation
• green hair caused by copper, not chlorine
• sequestrants’ benefits and degradation over time
• chlorine-first method for algae removal at 25 ppm
• in-water stain removal using acids and metal media
• faster metal capture with a canister and aux pump
• tracing metal sources from equipment and surfaces
• pebble finishes with iron and spot remediation
• learning path with guides, books, and courses
• links to podcasts and coaching resources

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Chapters

• 0:00 Welcome And Topic Overview
• 2:10 Coaching Program Invitation
• 2:29 Copper Systems On The Market
• 2:52 What Copper Kills And Its Limits
• 4:00 Oxidation Needs Beyond Ionizers
• 6:06 Speed Of Kill And EPA Guidance
• 7:28 Low Chlorine Risks With Bathers
• 8:47 Green Hair Explained By Copper
• 11:10 Copper Algaecides And Stain Risks
• 13:08 Why Sequestrants Degrade Over Time
• 15:23 Chlorine-First Strategy For Algae
• 16:34 Removing Copper Stains In Water
• 20:05 Kits And Accelerated Metal Removal

Transcript

SPEAKER_00: 1:03

Hi, welcome to the Pool Guy Podcast Show. In this episode, I'm going to do a best above Lowry, and we're going to talk about copper in the pool, using copper in the pool, specifically copper algicides, and is using copper safe in a swimming pool. We're going to cover all things copper in this episode. 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. Let's talk about uh copper in the pool. And there's a lot of products out there. They call them nowadays they call them mineral technology or mineral systems. I don't know what they were called back in the olden days. Uh, but you have things like the frog, the nature to the pool RX, and even the solar ionizers that float in the pool and the sun hits the top, and then um that also adds copper to the water. Now, copper, of course, is a great way to prevent algae. And I've even heard customers or you know referred to putting like a copper anode in their skimmer basket, it's like a piece of copper. So copper does kill algae, right?

SPEAKER_01: 2:19

Yes, actually, copper at a at a low level kills algae, and a little bit higher level it kills bacteria. So you can kill bacteria and algae with copper. The problem is that there are a number of problems with doing that. First of all, the level at which it kills algae and bacteria is right at the edge of the level where it causes stains. So if you use it, you have to use a sequestering agent or a chelating agent in the water to prevent staining. Also, understand this. When people sell the ionizers, they claim that this kills bacteria and algae, and your pool will be algae and bacteria free. Well, you realize, of course, that when you add chlorine to your pool, that about 15% of the chlorine goes for killing algae and bacteria, and 85% of it goes towards oxidation of sunblock and sweat and urine and and all the stuff that's on our bodies when we get into the pool. If you use a copper ionizer in your pool, it doesn't oxidize anything. So you need a separate oxidizer and you need a lot of it because you're gonna have to get rid of all of that stuff, all of that sweat, urine, sunblock, all those things. And a non-chlorine oxidizer is probably not strong enough to get to to destroy most sunblock because it's a complex molecule, and the oxidizer just doesn't have enough oxidizing power to do it. Chlorine does, uh, but even chlorine may not kill some sunblocks. You know, they make them that way so that they don't break down, so you can put them on your body and they'll they'll last. And they even make them now so they're waterproof, but they still get in the water. Once they get in the water, chlorine has to spend a lot of time trying to to oxidize it. At any rate, uh I I think that again, the right chlorine level is where we need to be. But copper, the other thing that copper does not do, it kills algae and it kills bacteria, but it doesn't kill it very quick. And I've talked about this with you before about what we call bather-to-bather disease transmission. And copper is not strong enough, not a good enough uh bactericide to kill bacteria that comes from you, gets in the water, and gets on me. It's not fast enough to kill that bather-to-bather disease transmission. You have to have something in the water. EPA has said that you can use an ionizer, but you have to use chlorine with it. You can use a low level of chlorine, but you need to use chlorine with it. And then there is a problem with keeping a low chlorine residual. And I think I've talked about uh this with you before, and that is when you keep a low chlorine residual, when you get a number of bathers into the water, they wipe out your chlorine residual, and now you got no chlorine residual all over again. Keeping a low level of chlorine with copper in the water, as soon as you get bathers in the water, your chlorine's gone, and now you don't have any protection in the water against the disease uh bather-to-bather disease transmission.

SPEAKER_00: 6:19

And one side effect I think that you hear about a lot, and it's not an urban legend because this has happened, is if you have light hair, blonde, and there's a high level of copper in the water, and then there's a high level of chlorine in the water, your hair will actually turn green.

SPEAKER_01: 6:36

It's true that copper in the water causes green hair. Chlorine in the water does not cause green hair. No chlorine in the water causes green hair. The the reason that that people think that chlorine causes green hair is they put tablets of chlorine in their skimmer, and then the acid from the tablets dissolves part of their copper heater, and it gets into the pool, and once the level gets high enough beyond the saturation point, we have copper in the water. You put people in it, and and it makes their hair and fingernails green, and to make your pool green if you leave it long enough. So people think that the chlorine tablets cause the problem. But think about it, chlorine is a bleach. It's not a dye, it doesn't make things green, it makes things white. That's why we put it in the washing machine. It makes things white. It doesn't, chlorine doesn't make anything green. Uh copper, yes. And copper sulfate is the most common cause. And it actually bleed, it actually makes green on everybody's hair. But people with brown or dark hair, when you put green on it, you can't see it. When people have gray hair or blonde hair, or young people that have new hair, um, is more susceptible to copper staining than uh people that have brown hair.

SPEAKER_00: 8:14

And I know we talked about algecides in the past. And what about those that that swear by copper algecides? I know they're highly effective, but we mentioned the fact that there's a certain level that will cause staining in the pool. And these copper algicides, the instructions on them are really specific. If you read them, they cost there's many cautions on there about using the proper amount. And so copper algecides have that danger of staining the pool in some cases, right?

SPEAKER_01: 8:41

That's correct. Although most of the uh algae manufacturers, the copper algae manufacturers, have put a sequestering agent in with the copper. So it's in the bottle when you pour it in your pool, and there's enough sequestering agent to prevent it from causing a stain, at least while you're getting rid of the algae. But understand that a sequestering agent is an organic molecule, and you're putting chlorine and oxidizers into the pool, and there's also sunlight there. So between those three things, they're going to eventually weaken and degrade that organic molecule so it doesn't work anymore. And this is the reason that most of the places uh that sell sequestering agents tell you you need to add them on a regular basis because they are degrading and you need to replace them. If you put an algecide in the water, and if you superchlorinate, you're going to degrade that that sequestering agent. So if you do that, you're causing a problem. Even though you think you're doing a good thing, you put in a copper algecide that's got a sequestering agent, and then you put in chlorine, and it destroys the sequestering agent, and now you've got a stain in the pool. Um, you need to follow the directions and do what it says. But again, I am a big promoter of using chlorine first. You've already got it on your truck. Uh it's easy, it's cheap, it's cheaper than buying an algacide. You put in 25 parts per million of chlorine, leave it for 24 hours, as we've discussed, make sure that the 25 ppm is maintained for 24 hours, and you're going to kill most algae. And then you go back to using your pool.

SPEAKER_00: 10:36

What about uh copper staining? This is very common. You mentioned we mentioned low pH causes some copper um staining from equipment, and then of course, overusing a copper algicide or ionizer, if we were to get to a certain level and stain the plaster or the pool surface, what's the best way to remove the staining of the copper on there, besides draining it and acid washing the pool, which is a pretty harsh level? What about something that you can do why there's still water in the pool?

SPEAKER_01: 11:04

Well, one of the things that you can do, understand too, that if you use a sequestering agent, all it does is surround the metal ions with the molecules so that the metal ion can't attach to anything else. So the metal is still technically in the pool. It just can't combine with anything and make a stain. So we want to remove the metal from the pool. And as you've said, if there's a stain on the pool, we can acid wash the pool. But aside from that, we can use one of these products, and you can use a brand name, but there are these little bags and cages that you can put into the skimmer that remove the metal from the pool. And again, we talk about saturation points, and if you take metal out of the water, there's more room in the water for metal. So you take some of the metal out, the stain that's on the wall can redissolve into the water. You take some more metal out, and the stain that's on the wall can redissolve into the pool. So by removing metal from the water, you can remove the stain from the pool. You can also use a metal remover product that removes the stain but doesn't remove the metal from the pool. You can use that in conjunction with the metal remover you put in the skimmer. So you can use a product that has ascorbic acid or citric acid in it, and it will take like a square, an ascorbic acid metal remover will remove the stain very well from the pool. But if you don't then get rid of that combined ascorbic acid and metal, if you don't get rid of that when you superchlorinate the ascorbic acid gets wiped out by the chlorine, you've still got the metal in the pool. So if you use, you can use as a one-two punch, you can put ascorbic acid in the pool, put a a bag in the filter or a little cage in the filter, and as it pulls it off of the wall, it'll suck it into the into the bag that's in the filter. But the the bag that's in the filter is gonna take perhaps a week or longer for all of the water to go through that that little bag that's in the skimmer.

SPEAKER_00: 14:06

And I guess we could mention that's a celator product. We we know the people there really well, both of us. And they actually have a kit. You mentioned all the products in their kit. Uh something that they came out with that's relatively new. Well, it's been on the market for a while, but they're trying to relaunch this kit, and it has the asorbic acid, it has a bag of citric acid, it has the celator Ultra 4.0, which is the little baggie that pulls the metal out, and it has their sequestering agent. So that is all in one kit. And you kind of need that, right, for the whole removal without draining and acid washing, as you mentioned. So it's kind of smarter than to put it all in one kit, right?

SPEAKER_01: 14:46

Yeah, they they also do have a separate uh canister type filter that's that uh has a cartridge that you put into it that's impregnated with their technology. And what you can do to speed things along is if you've got a a separate pump that you sometimes use for for your vacuum or for draining or something, you can set a pump beside the pool, draw water in from one side, run it through the the filter that removes the the metal and put them put the hose back in the pool, let it run for a while. Which is a much more efficient way of doing it than just putting a bag in the skimmer.

SPEAKER_00: 15:31

You know, once you have the copper staying in the pool, that's when you s you start to have to also be detective and find out where it's coming from. You just can't eliminate it without finding the source because then it could come back in the pool.

SPEAKER_01: 15:44

Right. It can be from a number of things. It can be from a copper algicide, it can be from incoming water, it can be from using uh trichlor tabs in the skimmer, uh, it can be from overfeeding uh anything that's acidic. It can be from, believe it or not, water velocity. You can be running the water too fast through anything that has metal in it, and it's eroding the metal rather than corroding it. And so there's an erosion that happens because of water velocity. Um, these things are are important to understand.

SPEAKER_00: 16:25

Yeah, and I guess one more source that is something that you don't hear about a lot, but we've been finding this to be a problem, is in a brand new pebble tech pool, they they do a lot of work to get the metals out of the pebbles before they process them. But there's been a lot of cases lately. I don't know if it's because they're having too many orders and because of all the building going on, but there are some of the pebbles that have metal in it, and then in the pool, there'll be a spot forming on the bottom, like a rust spot, sometimes as big as a nickel, sometimes smaller, and that's actually the surface of the pool causing the problem.

SPEAKER_01: 17:02

Yes. And uh it's it's not too uncommon for certain areas of the country where they they mine the the pebbles in the rocks to have iron in them. And so uh when the iron sees the light of day and some chlorine, um now all of a sudden we we get a brown-colored stain or a yellow-colored stain uh on the surface, and it's because there was iron in the in the rock.

SPEAKER_00: 17:29

Yeah, and the remedy is kind of unusual. They actually will go down there or dive down there with a little pick and take that pebble out, which is kind of interesting. So, yeah, so metal can get in the pool in all different ways. That that's just to say that if you have to really figure out where it's coming from, um, otherwise it could be a continuing problem. But I thank you again for all these recordings. I think we covered a gambit today of subjects, and like always, the pool pro benefits and the homeowner benefits also from your knowledge and you know.

SPEAKER_01: 18:02

I try to bring everything down to a level that the guy on the street can understand it.

SPEAKER_00: 18:07

And I think you do, effectively, you do that, and with all your material, and I especially like your books because not only are the illustrations really helpful, but just the way that you've wrote these guides and all the the books that you've published. Anyone with any with with no knowledge of chemistry, with zero knowledge, or maybe they were asleep during the chemistry class in high school, they pick up your book, and just from the drawings and the illustrations and the diagrams, they could figure out basic pool chemistry.

SPEAKER_01: 18:37

Well, even for the pool guys, we've had some pool companies that have uh multiple employee uh service techs working for them, and they call me and say, What do I do? I got a brand new guy that knows nothing about pools. And in that case, I tell them to get instead of the pool chemistry for service pros book, I tell them to get the easy pool chemistry book, which is for homeowners. And I tell them, read this one first, and after you read it maybe twice and understand it, then get the pool chemistry for service prose book and you'll understand it. And then if you take and then if you take the course, you'll be all set.

SPEAKER_00: 19:19

Yeah. I should say the the book you referred to is only about 20 pages, the pool chemistry for prose. Is that the one? Is that the other one?

SPEAKER_01: 19:28

It's a 28-page book, but it's you know, when you when you think about the table of contents and you know the empty pages and stuff like that, it's it's only about 20 pages. You can flip through it real easy. And we tell we have guys they just keep the book on their truck. It's easy to refer to because it has so many drawings and stuff. When you go to look something up, you know where what drawing or what the what it's what is what's you're looking up, what is near in the book. So it makes it easy to look things up.

SPEAKER_00: 20:00

So well, thanks again for your time today. I don't want to take too much more of it up, and I appreciate these monthly podcasts. I'm sure the listeners do as well.

SPEAKER_01: 20:08

I'm glad to do them. My goal is to make pool owners happy and for us to have a bigger industry. Yeah. And and that's my goal. I don't have anything to sell you people except education. If you want to buy a book, buy a book. But uh I I just I I want our pool industry to get bigger, and I want the people that have a pool to be happy with what they got.

SPEAKER_00: 20:32

If you're looking for other podcasts, you can find those by going to my website, swimmingprolearning.com, on the banner. Click on the podcast icon. There'll be a drop down menu with over 1,800 podcasts there for you. And if you're interested in the coaching program that I run, you can also learn more at poolguycoaching.com. Thanks for listening to this podcast. Have a rest of your week and God bless.