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Common Pool Sanitizer Mistakes

Pool care can be tough with many choices on how to get the job done right. Everyone’s looking for new ways to keep pools cleaner or use less chemical.

Owning and maintaining a swimming pool brings plenty of opportunity for error when it comes to water balance. Big or small, making those types of mistakes can really throw a wrench in your plans. 

But mistakes are really just opportunities to learn, right? Educating yourself on the most common pool sanitizer blunders helps you keep the pool safe, clean, and running efficiently with less “mess” and frustration.

Along with proper care and maintenance, you too can avoid making these pool sanitizer mistakes.

1. Can a pool use zero chemicals? 

There is no perfect solution or magic “pool pill” when it comes to pool water purification. The truth is we would love to have perfectly clean water without all the harsh chemicals. 

But, chlorine has been an effective residual sanitizer for ages. And in our humble opinion, there is no real substitute for something that keeps swimmers safe even when the pump is off.

Chlorine is the “go-to” choice in pool sanitization for pool professionals and homeowners alike and is unlikely to go away anytime soon. 

Let’s take it even further and address the differences between what we call an “active sanitizer” versus a residual, like chlorine.

★ Active Sanitizer vs Residual Sanitizer and trying to eliminate chlorine from their pool. 

The residual sanitizer is what you have out in the water at all times, actively keeping the water clean. This is super-important because a residual is always at the ready. 

Algae enters the water – boom – residual. Biofilm tries to grow – boom – residual. The whole soccer team comes over and gets in the pool – boom – residual!

It is really easy to get fixated on the idea that pools can be maintained without chlorine/chemicals. But if there’s no sanitizer in the water, you are going to be in trouble. And you need enough sanitizer in the water to overcome the demand as more swimmers get in the pool.

What we call supplemental residuals do actively sanitize, but they will not be enough on their own. They need a backup, i.e. chlorine, to help keep the water clean. That’s why we consider them an “addition” because they need to work alongside something else.

You can get the most out of a chlorine system—like a salt chlorine generator system— by adding a powerful advanced sanitizer like AOP or an ozone/ UV system. AOP makes salt better by requiring less chlorine and reducing overall chlorine usage. And essentially, you get more bang for your buck from the chlorine generator.

2. Is a salt pool chlorine free?

The short answer is no. Simply put, salt comprises two elements: chlorine and sodium. A salt chlorine generator (SCG) is a very convenient way to sanitize a pool with chlorine, without needing to store buckets of tabs and pool shock.

A chlorine generator electrically creates Hypochlorous Acid (HClO) in the water, the killing form of chlorine. It creates the purest form of it too. And, because you’re generating it right in the backyard, this puts you in total control of the water balance.

Did you know liquid chlorine is made using a salt chlorine generator? They make it at the factory just like you do in the backyard, but on a much larger scale. This, by the way, is why liquid bottled chlorine has a salt content. You can buy jugs of liquid chlorine—or just skip that part and make it yourself.

3. Should I use Salt or Ozone/UV? Or both?

What if we told you it wasn’t either or, but both? Wait. What? You mean I should be using both an advanced sanitizer and a salt chlorine generator?! 🤯

Next Gen AOP™ and Powerclean® Salt on a pool pad.

Yes! They complement each other perfectly, and you get a different set of benefits with each system. Advanced Oxidation Potential (AOP) is the cream of the crop as far as modern sanitizer technology for swimming pools and spas goes. It can destroy microbes that chlorine will take hours or days to kill on its own.

The Ozone/UV or AOP system obliterates pool nasties in record time and is even more powerful than ozone. But, you still need a residual to keep swimmers safe from harmful bacteria and viruses when the pump is off right? This is where the salt system comes into play. An SCG produces and maintains the perfect level of chlorine needed for that.

4. Does chlorine cause dry skin?

Do you think you’re allergic to chlorine? Chlorine in the pool combines with contaminants like sweat, oil, urine, and other yucky stuff, creating chloramines. It’s gross but true!

It is these chloramines that can cause red, itchy, irritated eyes and skin . . . and that funky chlorine smell! Trapped indoors, chloramines can go airborne causing lung irritations and breathing problems.

Almost all negative reactions, or “allergies” to chlorine are actually reactions to chloramines. The good news is you can easily prevent chloramines with things like AOP or ozone + UV.

5. Do I need an MDV with my pool? 

We handled this debate in our recent Ozone Myths & Misunderstandings video. There is a myth circulating that indicates DEL systems always require a Mixing De-Gas Vessel (MDV), which prevents undissolved ozone gas from returning to the pool. It sounds like you always need more equipment with a DEL system. Let us set you at ease. Every pool does not need an MDV. It has a very specific purpose. 

So, when do I need an MDV?

1-if you are concerned about a vinyl liner fading near the ozone outlet

2-if you keep the pool covered most of the time with the ozone running

3-if the pool is indoors

4-if for some reason you just hate seeing bubbles

Really, the vast majority of pools do not need an MDV. It is an extra tool that we provide so each pool can have the best possible installation. Some of it comes down to particular needs, and some of it is personal installer preference.

6. Do I shower before or after I swim?

Let’s just take a moment and think about what everyone is bringing into the pool with them. Exactly.

Unlike in Europe and some other areas outside the US, it is not common practice to shower before a swim. Every person brings a lot with them into the pool like body oils, makeup, lotions, dust, dirt, grass etc. All of that comes into the pool. And we know it’s gross, but you should know any feces or urine on the body is also going into the water. 

All of that “stuff” puts a huge demand on the water. Chlorine and other sanitizer systems have to put in a lot of extra work to keep the water clean. You can help make it easier for sanitizers to keep the water crystal clear with just a little elbow grease.

There are a few simple things you can do, including brushing your pool walls, that will feel magical when you see the difference it makes in the pool.

7. Do I really need to brush the walls, won’t chlorine fix that?

Most of us underestimate the value of physically cleaning the pool. It’s tempting to rely only on chemicals. But, do you just pour soapy water on your floors and let it dry? Most likely you do some SCRUBBING!

The same is true for pools. Sometimes you just need to grab a brush and scrub the walls, steps and floor. Dirt, oils and algae can all build up on the wall in ways that chemicals can barely touch them. 

Don’t be afraid of the pool brush!

Ever heard of biofilm? It’s a funky mix of bacteria, dirt and oils that can grime up pool walls and get into the plumbing. Chlorine breaks some of this down, but scrubbing will help break it up more and get it off the walls much easier. All of this can help save your equipment, because it won’t have to work as hard. 

Weekly brushing helps loosen surface dirt so the filter can pick it up during filtration cycles.

The simple act of physically cleaning a pool will do wonders for the pool. Like the other steps, this little bit of physical work will allow you to use fewer chemicals and yes, even save you money.

8. Salt systems are not maintenance free.

Pools using traditional chlorine systems typically experience sharp peaks and valleys of chlorine levels depending on bather load and other factors. So, you end up having to put a lot of work into balancing the water chemistry. Sometimes this can feel like a never ending cycle.

Salt systems are not maintenance free. But, we have made one that is easy to clean and maintain, and it has some other awesome features that make it the friendliest chlorine generator available on the market!

Powerclean Salt installed on a pool pad.

Powerclean Salt Features & Benefits:

Clean with Zero Acid – remove the cell completely for cleaning without harsh chemicals

Wider Spaced Plates – cell plates are further apart to prevent “scale bridging”

Clear Cell Housing – you can easily see when it’s time to clean the unit

Smart Sensor – cells constantly update the control center for dynamic adjustments

Intelligent Operation – conductivity adjusts to extend the life of the unit

More Durable – a heavy duty heat sink lets the system function in high temps

9. Can I JUST use AOP on my pool/spa?

This question touches on the previous one. AOP provides powerful oxidation. However, we mentioned how you still need an active residual in the water to help keep swimmers safe at all times, even when the pump is off.

AOP uses ozone, which can exit into the pool and leave some residual. However, this residual is very short-lasting, hard to control and only around when the system is running. At best ozone has a half-life of just 12 minutes in typical pool temperatures.

🎞 Check out this video demonstrating how quickly AOP gets to work on pool nasties.

Ozone does most of what it needs to inside the pipes before it even makes it into the pool. And like we said above, the amount isn’t enough to maintain the residual at a meaningful level. Commercial systems are too costly for most residential applications, and are not a good fit for backyard pools. 

For this reason, we recommend you keep chlorine as the residual sanitizer for your pool. But ozone can replace your chlorine shock treatments! #WIN

10. Does my ozone or AOP unit have a pump inside to push out the ozone?

All products that use DEL Ozone inject the actual ozone bubbles with something called “venturi injection.” With a venturi, fast-moving water moves past an air opening, creating a suction effect. So instead of pushing ozone into the water, it actually “sucks” the ozone through. It is effective and efficient – we reuse the energy of your pump to inject the ozone instead of requiring extra pieces of equipment. 

Every Mistake is a Chance for a Better Pool Experience

One thing’s for certain . . .  no one is perfect! Every flub is an opportunity to improve your game. And learning from your mistakes helps you keep the pool running smoothly in the long run.

New products outfitted with the latest technology can help minimize some of the work and save you time. Next Gen AOP and Powerclean Salt do some of the dirty work up front and help lower overall chlorine use, so you can get around to all the little things that help make a better pool experience.


Technology has come a long way, and so have pool sanitizers. When looking at chlorine and chemical-free options, the answer isn’t always either/or. By combining the best available technologies, every pool can be crystal clear and absolutely safe. Visit c-m-p.com/modernpool to learn more.

For more CMP videos, subscribe and follow @cmppoolspa.

More Posts

[Video] Simple Ways to Reduce Pool Chemicals

Salt or AOP UV/Ozone? Or Salt AND AOP UV/Ozone?

Pool School: Back to Basics

[Video] What is the Best Pool Care Chemical?

Swimming Pool Ozone Myths & Misunderstandings


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