Bob Lowry: Should You Ever Add Copper to a Pool?

Copper sounds like the perfect pool hack: add a “mineral system,” fight algae, and use less chlorine. The reality is more complicated, and that gap between marketing and chemistry is where stains, green hair, and unsafe water conditions show up. We’re joined by industry legend Bob Lowry, whose voice and teaching still carry weight across the pool industry, to give a clear-eyed answer to the question pool owners ask every year: is copper safe to use in a swimming pool?

We talk through how copper ionizers and mineral technology products work, what copper actually does well (algae control, some bacteria suppression), and why the “copper replaces chlorine” idea breaks down. A big theme is oxidation: copper doesn’t burn off sunscreen, sweat, and other bather waste, so the pool still needs an oxidizer, and chlorine remains the most practical tool for that job. We also dig into real-world safety, including bather-to-bather disease transmission and why copper is too slow to be your primary sanitizer, plus what the EPA requires when ionizers are used.

Then we get hands-on with the problems people see most: copper staining on plaster and the green-hair myth. We explain how copper gets into the water (including trichlor tabs in skimmers attacking copper equipment), how sequestrants degrade over time, and a smarter “one-two punch” for stain treatment using ascorbic or citric acid alongside products that actually remove metals from the water. If you want fewer surprises and better pool water chemistry, subscribe, share this with a pool owner who loves shortcuts, and leave a review telling us what copper problem you’ve run into most.

We sit down with industry legend Bob Lowry and get honest about copper in pool water, from mineral systems to copper algaecides, and why the chemistry can turn on you fast. We break down what copper is good at, what it cannot do, and how to fix copper staining without draining the pool.  
• copper mineral systems and how they add copper to the water  
• copper’s algae control benefits and why the effective level is close to the staining level  
• why copper does not oxidize bather waste like sunscreen, sweat, and urine  
• bather-to-bather disease transmission and why copper is not fast enough  
• the EPA position on ionizers requiring chlorine alongside them  
• the real cause of green hair and why chlorine is not to blame  
• copper algaecides, built-in sequestrants, and how chlorine and sunlight degrade them  
• a chlorine-first approach to killing algae and why it is cheaper and simpler  
• stain removal without draining using ascorbic or citric acid plus metal removal bags  
• tracking the metal source including tabs in skimmers, incoming water, equipment, water velocity, and new surfaces with iron  
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Transcript

Welcome And Bob Lowry Tribute

SPEAKER_01 1:03

Hey, welcome to the Best of the Pool Guy Podcast Show. In this episode, I sit down with industry legend Bob Lowry, who passed away in 2021. But of course, his legacy lives on in the industry. We sit down and we talk about copper and is it safe to use copper in your swimming pool? 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 swimming poollearning.com. 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. But you have things like the frog, the nature 2, the pool RX, and even the solar ionizers that float in the pool and the sun hits the top, and then 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_00 2:15

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

Copper Mineral Systems And Claims

SPEAKER_00 2:29

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%

Staining Risk And Oxidation Gap

SPEAKER_00 3:22

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, 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 oxidize it. At any rate, 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 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

Why Copper Is Too Slow

SPEAKER_00 5:40

about 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 bather-to-bather disease transmission.

SPEAKER_01 6:11

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 hair, 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_00 6:29

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 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.

Green Hair Cause And Copper Algaecides

SPEAKER_00 7:00

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 it'll 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. 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, is more susceptible to copper staining than people that have brown hair.

SPEAKER_01 8:28

And I know we talked about algicides 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 algacides have that danger of staining the pool in some cases, right?

SPEAKER_00 8:55

That's correct. Although most of the 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 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 algeide 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 algicide that's got a sequestering agent, and then you put in chlorine and it destroys the sequestering agent, and now you got a stain in the pool. 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. 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_01 10:49

And what about copper staining? This is very common. You mentioned we mentioned low pH causes some copper staining from equipment, and then of course, overusing a copper algacyte 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 while there's still water in the pool?

SPEAKER_00 11:16

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

Removing Copper Stains Without Draining

SPEAKER_00 11:45

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 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 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_01 13:57

And I guess we could mention that's a C later 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. 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 sealator Ultra 4.0, which is the little baggy 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_00 14:37

Yeah, they they also do have a separate canister type filter that's that 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_01 15:21

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_00 15:35

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 trichlor tabs in the skimmer, it can be from overfeeding 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. These things are are important to understand.

SPEAKER_01 16:14

Yeah, and I guess one more source that is

Finding The Source And Closing

SPEAKER_01 16:16

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_00 16:51

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 when the iron sees the light of day and some chlorine, and all of a sudden we we get a brown-colored stain or a yellow-colored stain on the surface, and it's because there was iron in the in the rock.

SPEAKER_01 17:16

If you're looking for more podcasts, you can find those by going to my website, swingingprolearning.com, where I have over if you click on the podcast icon, I should say, it'll bring down a menu over 1900 podcasts for you to listen to at your leisure. If it's in the coaching program that offer, you can learn more at PoolGuyCoaching.com. Thanks for listening to this podcast. Have the rest of your week. God bless.