Salt Water Pool Pros and Cons – Advice from Bob Lowry

“Salt pool, no chlorine” might be the most expensive misunderstanding in pool care. We walk through what a saltwater chlorine generator actually does, why it is literally making chlorine, and how that simple truth changes the way you test, dose, and explain water balance to customers. If you’re a pool service professional or a hands-on pool owner, you’ll leave with clearer language, better troubleshooting steps, and fewer surprises on Monday morning.

We also get into the parts that sales sheets skip: salt splash-out that dries on decks and hardware, the corrosion that shows up when salt is over-added, and why bonding and grounding matter more once your pool becomes an ionic solution full of metals. 

Then we tackle the “flakes” problem and the myths that cling to it. We explain why flakes are usually calcium carbonate, how a hot cell after flow stops can trigger scale, and how a simple cool-down period plus a slightly negative LSI can reduce buildup. 

• saltwater systems generating chlorine through electrolysis, same sanitizer as liquid or dry chlorine
• cell lifespan tied to total run hours, lowering output and run time when demand allows
• manufacturer salt targets around 3,000 to 3,500 ppm and why over-salting creates new problems
• salt splash-out leaving concentrated salt on decks and features, rinsing to prevent crust and damage
• galvanic corrosion risks, black deposits near metals, bonding and grounding pool equipment
• heater corrosion concerns and when a sacrificial zinc anode can help
• dealing with a failed generator, draining and refilling to reduce salt and high TDS, removing the cell housing
• verifying salt with an independent salt meter, not trusting onboard readings or a TDS meter alone
• preventing flakes with a cool-down period before flow stops and managing LSI slightly negative
• phosphate fears put in perspective, flakes usually calcium carbonate not calcium phosphate
• fixed-output chlorine production, recovery time after bather load spikes, supplementing with liquid chlorine
• “superchlorinate” misconce

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Transcript

Setup And Sponsor Mentions

SPEAKER_01 1:15

And if you're interested in selling these on your full graph or if you're just taking any one of these yourself, this is definitely the episode for you, or Bob Lowry explained slot order generators, and the benefits and some drawbacks as well. Are you a full service pro looking to take your business to the next level? Join the Pool Guide 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 tool to help you succeed. Learn more at swimmingfullearning.com. But let's talk a little bit about saltwater generators now. And these are something that's that's really been a big, a big thing since the big three started making them, you know, Jan, a fluidra, I should say, Penter and Hayward. Once they discovered that these things were selling, they started making their own saltwater generators, and then they're advertising them in different ways, many different ways they advertise them. But I think one way that I've seen advertise is that this is a chlorine alternative, and that's one kind of marketing technique. But a saltwater generator basically generates chlorine. As you mentioned, you call them chlorine generators, right?

SPEAKER_00 2:24

Yeah, you know, the one of the things that I hear all the time, even back in the 90s, I heard about it. We have a salt pool, we don't use chlorine. And I really almost shudder every time I hear somebody say that because they don't really understand what they bought. And the simple matter, the simple fact of the matter is, if you have a salt pool, you put salt in the water, and that little chlorine generator, that little cell, it it applies electricity to the water that's going through it, and there's salt in the water, and the chloride in the water changes into chlorine. And the chlorine dissolves in the water, and it's the same thing as if you poured some liquid chlorine in or put some dry chlorine in the pool. Chlorine is chlorine. So if you have a salt pool, you're using chlorine. And if you don't believe it, just get a chlorine test kit and see how much chlorine's in your pool.

SPEAKER_01 3:28

I think also, Bob, what's funny is when you look at the manual, which no one actually looks at it, I don't think anymore. But in there, the manufacturers say that if you run this generator for 24 hours, it's going to produce 1.2 pounds of chlorine. It actually says in the manual that it is making chlorine. So I think that that's kind of funny.

Salt Levels And Corrosion Reality

SPEAKER_00 3:47

Yes. So it it does, it will if you do that. If you run it, of course, 24 hours at 100%, it won't last very long. Yeah. Because the life expectancy of a salt generator is strictly based on how many hours it runs. And so the longer it runs, the shorter the life. And so the shorter we can run it, the better. It'll last longer. So a chlorine generator actually, you put the salt in the water, and you have to put in the amount that the manufacturer claims that or may recommend. And they usually recommend between 3,000 and 3,500 parts per million of salt. And that in a typical pool is about 400 or maybe 425 pounds of salt. So you put that in the pool and then turn on the generator and it starts making chlorine. And you the the only setting really on it is what percent of time it is on. And you just set it on a percentage that will maintain the amount of chlorine that you want in the pool. But you can you can help things along by using less chlorine. By using less chlorine, you can put borate in the pool, and you won't need as much chlorine because the borate's preventing the algae. So you can turn it down. So the pH isn't going to go up so much. It also isn't going to be uh making any scale on the on the electrodes that are inside there, on the plates that or cells that are in there. Uh it's not going to be creating uh deposits on. These devices are there, they are a great thing, but you must understand that that you are putting salt in your pool. While it's not the same thing as the ocean, the ocean is about 35,000 parts per million of salt. The pool is about 3,500 parts per million of salt. So it's only one-tenth of the ocean. And the amount of salt is actually equal to almost the salt that's in your tears in your eyes, anyway. So it it doesn't burn your eyes or anything else. It can feel a little bit a little bit different than regular water, so it can't have a different feel to it. So you can open your eyes underwater and so on. But the things that you need to think about are that the salt water chlorine generator, the salt that's in the pool, they say that it's not a very strong solution of salt. And they're right. But what happens is the water that gets spliced out of the pool onto the deck, the furniture, the slides, the water features, whatever, when that water evaporates, it sits there on there and it evaporates. When it evaporates, it leaves behind salt. And regardless of who you are, salt is corrosive. And it's not corrosive when it's only 3,000 parts per million, but it is corrosive when it's 100% salt. So you need to think about that, and it may require some more maintenance on your part. And that is, if you've got a bunch of kids getting in and out of the pool, it's going to leave salt on your deck. You may want to rinse off your decks, you may want to rinse off your furniture, you may want to even rinse off some waterfalls or stuff so that you don't have salt left on it. Because it's eventually going to leave deposits, and the deposits are going to become crystallized, and then they're going to be hard to remove.

SPEAKER_01 7:54

And I think it's important to note also, Bob, that if you add the amount of salt above the recommendation, which happens a lot in the industry because a pool guy may come to a salt water system that's not working, and he'll just think, well, it says low salt, so I can add more salt. That's right. And it may raise it to five or six thousand, and then that becomes corrosive.

Bonding Grounding And Sacrificial Anodes

SPEAKER_00 8:18

Yes, and so it becomes even more corrosive, but the the unit doesn't function very well when it gets too much salt either. Too much salt's not a good thing, and too little salt's not a good thing either. If there's too little salt, it doesn't make as much chlorine, so it takes longer to make it. But when you get too much, it actually can start to cause problems with the fact that you've got metals submersed in an ionic solution. And that's another thing that you need to be thinking about is that a pool with 3,500 parts per million of salt, plus the TDS that's already in the pool, which means that all of those things together could be maybe 5,000 parts per million, you actually have created a low voltage battery in your pool. Your whole pool is a low voltage battery. And that means that you need to bond and ground all of your electrical components in and around the pool. They need to be grounded. And by grounded, what you do is you take a copper wire and run it to each piece of equipment and then run it to a stake in the ground. So it's grounded. And you can get galvanic corrosion in a pool that's not properly grounded, and you can see what looks like a black deposit that starts around the light rings, or around the ladder, or around any of the metal parts in the pool, you'll see some black deposits, and that's usually a metal that used to be someplace else, because lower activity metals gravitate towards higher noble metals. That deposit that that is around the light ring perhaps used to be part of your heater.

SPEAKER_01 10:12

Yeah, I know that the heater parts definitely will take some hit from the salt water generators, particularly if you have a pentair heater, the thermal regulator will corrode quickly in there. And RayPack has a new heater out where they have a special, I don't know what they have, like an anode in there, so it keeps that corrosion from salt water and pools out of there.

SPEAKER_00 10:37

Some pools need that. And it's just actually a little round zinc ball. And zinc is one of the lower, lower metals as far as nobility goes, and you put it in and it will sacrifice itself so that the other metals don't. So it's a way of protecting the other metals in the pool by putting an anode in your pool. So that's a possibility. But you really need to be grounding the pool equipment.

SPEAKER_01 11:05

And then also I was going to ask you too, you know, a lot of times the customer will have a salt water generator and then they'll just turn it off because it's not working. What would be the side effect then of taking over a pool that has, you know, TDS of 5,000 at that point now that the saltwater generator is off?

What To Do When It Fails

SPEAKER_00 11:23

You know, you still have the problem with corrosion, depending on on how you're going to chlorinate it, whether you're going to use tabs or liquid or whatever, you may uh you may be creating some problems. And I think if you're not going to leave the pool, if you're not going to to revive the chlorine generator or replace it, then I think I would probably drain, I don't know, 75% of the pool and fill it back up and get rid of all of that salt because you still have the same problems that I discussed with grounding and corrosion and and leaving salt on the in and around the pool, you still have all of those problems, and and yet you're not generating any chlorine. So and I would also make sure that you remove the device. Don't let the water keep running through there. Remove it. I think the best thing to do would be to drain drain most of the water, refill it to get rid of most of that salt, because all that salt is something you don't need, and you don't need that high TDS either. So I would get rid of it. One of the things with a working chlorine generator that you need to check is that most of the chlorine generators come with a salt meter, but who knows how the salt meter is calibrated. And so what I would do is I would use your own salt meter, not TDS meter, a salt meter, measure the salt level in the pool, and then check the the on-board salt meter with with the chlorine generator and see if it's got the proper reading. And I've had a number of guys that have called me up and said, I don't understand, man. You know, I've my salt meter on the on the chlorine generator says I got enough salt. And I go, what's the salt level in your pool with a salt meter? And they find out that they've only got 2,000 parts per million of salt in the pool.

SPEAKER_01 13:59

Yeah, it's a very common problem where the system reading is not gonna accurate for different reasons. I know with uh certain brands, like for instance, the Hayward Alkyrite system, if this if the cell gets calcium buildup on there, that system will read a false low level. And also when the salt cell is dying near the end of its lifespan, it'll read a low salt level. And that's where that where the technician will keep adding salt to the pool based on that.

Salt Meter Errors And Testing

SPEAKER_00 14:25

So you need to be checking that with a good salt meter, and don't just use a TDS meter, get a salt meter, or get a meter that reads both so that you can switch back and forth. Some other things that you may want to do, if possible. I don't know how the electronics are. Frankly, I've not kept up with some of the intelligent stuff that's out there or smart stuff, but you want to turn the chlorine generator off before the water flow stops. And the reason is that the chlorine generator actually gets hot, but when it's running at 40 or 50 or 80 gallons a minute of water through it, it's cooling itself off. But if it just shuts down the water flow and the generator at the same time, the generator is still hot, and the water that is in the generator warms up, and the warmer the water, the more the calcium comes out. So if you want to prevent the flakes, you want to turn off the generator five or ten minutes before the water flow stops. And with the electronics that there are today, you should be able to do that.

SPEAKER_01 15:40

Yeah, it's very easy to do with the variable speed pump because the salt generators will stop at any speed under 1800. And so one trick that you can do is set the high-speed program, and then right after that, have the low speed come on, and that'll give you that kind of cooling off period.

SPEAKER_00 15:56

Right. That's one of the big reasons that we see flakes in the pool. I can say everything's right in my pool, I'll come on getting the flakes. And the reason is that you're almost boiling the water that's in the in the chlorine generator. And when the water gets really hot like that, the calcium comes out and it's fixed to the flakes. And then when you when you turn it on, some of the flakes come off. But when it reverses polarity, more of the flakes come off, and you keep getting flakes in the pool. And that's the reason. The other thing that you can do with a salt water pool is to keep a slightly negative uh saturation index. So if you're doing the saturation index or LSI, instead of keeping it slightly positive, keep it slightly negative, and that'll keep that'll limit the amount of scale that you could form on the generator.

SPEAKER_01 16:50

That's good. And what about phosphates affecting the salt water system? I've heard a lot of a lot of talk about high phosphates causing some of that, those flakes in the pool.

Flakes Scale LSI And Phosphate Myth

SPEAKER_00 17:02

Yeah, you know, I've got a I've been asked that a lot, and my usual answer is it's phosphates are not a problem. They say, well, aren't the aren't the flakes calcium phosphate? And my answer is no, they're not. The reason that they're not is I want you to think about mathematics for a minute. When we say there is a high level of phosphate in the pool, we say that the level is like 1500 or 2,000 parts, parts per billion of phosphate. But you realize, of course, that uh it takes 1,000 parts per billion to make one part per million. So even though you've you've got a reading that you think is high and is 2,000 parts per billion of phosphate in the water, it's only two parts per million. How much could you precipitate out of the pool if it's only one part per million in the pool? So it's probably not cal, it's not calcium phosphate that's coming out of there. It's calcium carbonate. Because what what do you got calcium carbonate? You got 400 parts per million of calcium carbonate in calcium hardness. So it's calcium carbonate, it's not calcium phosphate.

SPEAKER_01 18:23

And so the way to solve that would be to make sure the generator has a cooling off period. And the Pool Bay podcast show is teamed up with UPA to bring you affordable, reliable liability insurance starting at$64 a month. Get up to$2 million in coverage, and the members of my coaching group get an even lower rate. Protect your business and your peace of mind. Sign up with UPA today by clicking the link in the podcast description.

SPEAKER_00 18:56

That's right. Make sure it has a cooling off area. Um years ago, maybe you remember it, we used to call it a a fireman's switch on a on a heater. And it turned the heater off a little a little while before the water water flow turned off to cool the heater down, to cool the heater in it now.

SPEAKER_01 19:16

Yeah, yeah, those still are around definitely for that reason, because you don't want that to be on when the pool's off. Uh when the pool turns off, you want a cooling down period. But great information on salt water generators there. I think you've touched on areas that no one really looks at beyond the uh the typical sales marketing sheet.

Fixed Output And Party Day Risks

SPEAKER_00 19:35

So well, one of the things that you also want to think about, and this doesn't, this has to do with with any device you're going to put on the pool, whether it's a chlorine generator, ozonator, UV, whatever. Remember a couple of things. One is that these devices only put out a fixed amount of chlorine. They are not bather or user generated, or it's not on demand. So it doesn't know that you put 20 people in there. So it puts out a fixed amount of something, and if you exceed that, then you have some time of no protection in the pool. And that is really important. Thing that we are trying to prevent in the pool is beter-to-bader transmission of disease. And if there's no residual in the water, there's nothing to keep me from infecting you and you to be infecting me. If there's a residual, when you let bacteria into the water, it kills it. It doesn't get to me. But if there's no residual, then there's nothing to protect beta-to-bather transmission of disease. So with a device, you can exceed what's it's what's in the water, and then there's a recovery time where there's no protection until it recovers. And how long is that recovery time? So you need to think about that when you're planning to take care of a pool. If you put a chlorine generator on there and it's one of those pools where every weekend they get 10 kids in the pool, you got a period of time where there's no chlorine in that pool.

SPEAKER_01 21:26

Yeah, and I think one of the misnomers is that when you have the superchlorinate mode on the saltwater generator, it's not producing more chlorine, it's just running at 100% output.

SPEAKER_00 21:35

It's running at 100% for a little longer time. And that's not superchlorination. Superchlorination is when you go out and put five parts per million of the chlorine in the pool in 30 seconds. Yeah, I think maybe they need to change five parts per million to the pool in in the next three hours.

SPEAKER_01 21:53

And I think they probably ch they have to change that on the devices because it kind of gives people the false safety or false idea that by flipping the switch to superchlorinate, the generator is actually producing more than it actually can.

SPEAKER_00 22:06

Yeah, they they the old way they used to say it was boost.

SPEAKER_01 22:10

Yeah.

SPEAKER_00 22:11

And all it did was boost it to 100% for two hours or something like that.

SPEAKER_01 22:17

Yeah, so I think I think that's uh something that you have to keep in mind with a salt water generator is if you have a pool party, you maybe need to supplement it with liquid chlorine after the party or during or before, especially if the pool is exhibiting signs of combined chlorine.

Where To Learn More

SPEAKER_00 22:32

Well, you know, even if you get a big rain, you know, in some areas, you know, in Florida where they get they can get you know an inch an hour of rain or something like that. If you get, you know, a few hours of rain in your pool, you're not gonna have any chlorine left in your pool.

SPEAKER_01 22:48

Yeah. Yeah, so true. It's not it's not it's not something that you can just set and forget about it. You have to really test the chlorine level just like a regular any other regular.

SPEAKER_00 22:58

It doesn't react to beta load. It doesn't dispense based on beta load. So it's not an on-demand device.

SPEAKER_01 23:06

If you're looking for other podcasts? You can find those on my website, swingprolearning.com. Just click on the podcast icon on the banner. There'll be a drop-down menu, over 1900 podcasts for you there as well. And if you're interested in the coaching program that I offer, you can learn more at PoolGuyCoaching.com. Thanks for listening to this podcast. Have a rest of your week. God bless.