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Automatic Pool Chlorinators: How Do They Work and Are They Worth It?

By Matt Giovanisci | Updated: January 12, 2022

Looking for an easier way to add chlorine to your pool? If you want to save time and stop worrying about your chlorine levels when you’re out of town, an automatic pool chlorinator can help.

What is an Automatic Pool Chlorinator?

Also known as an automatic chlorine feeder, an automatic chlorinator automatically dispenses chlorine into your pool. So instead of manually adding chlorine to your pool water or adding chlorine tablets to your floating dispenser or pool skimmer, you add chlorine tablets directly to your chlorinator.

The chlorine dissolves in the chlorinator and disperses into your water at a steady rate. That means consistent chlorine levels flow into your pool.

With a little upfront cost and installation, a chlorinator eliminates the need to constantly measure and add chlorine to your water or refill your floating chlorine dispenser.

Here’s a step-by-step guide on how automatic pool chlorinators work, the different types, and why they’re a great investment for most swimming pool owners. And if you’re in the market for one right now, here’s the one we recommend:

Our Top Pick
Hayward Automatic Pool Chlorinator (Inline)
Buy Now On Amazon
If you click this link and make a purchase, we earn a commission at no additional cost to you.

FYI: We’re a small team of pool industry experts and researchers that care about recommending quality, reliable pool products. If you choose to click a link and buy any of the products we recommend, we earn a commission at no additional cost to you.

How Does a Chlorinator Work?

An automatic pool chlorinator plugs directly into your pump and filter system, where it disperses a steady, measured amount of chlorine into the water that’s returning to your pool. As water passes through it, it slowly dissolves the chlorine tablet inside. It then dispenses that chlorine into your water based on your settings.

Simply add chlorine tablets to your chlorinator and choose your chlorine level (between 1 and 3 ppm) based on the volume of your pool. Then let the chlorinator do the work of adding chlorine consistently to your water!

With a pool chlorinator, you won’t need to add chlorine to a pool chlorinator as often as you’d need to add granular chlorine to your pool water. And you won’t need to worry about floating chlorine dispensers getting stuck behind ladders or adding chlorine tablets to your skimmer that can stain your pool’s vinyl liner.

But it’s not completely hands-free at the beginning. When you’re first using your pool chlorinator, be sure to regularly test your chlorine levels until you get a feel for the setting that works best based on your pool. And because pool chlorinators are part of your pool filter and pump system, they will not dissolve your chlorine tablets if your pool pump is off. So be sure to monitor your chlorine levels if you have a timer for your pool pump.

Wondering if a floating chlorine dispenser or putting chlorine tablets in your skimmer is a better option? Here’s a quick video tutorial on the difference between using floating dispensers, adding chlorine pucks in your skimmer, and installing an automatic pool chlorinator.

A pool chlorinator is not the same thing as a chlorine generator. A chlorine generator, also called a salt-chlorine generator or saltwater generator, actually creates chlorine from salt. That chlorine is then dispersed into the saltwater pool. A pool chlorinator, on the other hand, uses chlorine tablets to dispense chlorine into your water.

What are the Different Types of Automatic Pool Chlorinators?

There are two types of pool chlorinators: inline and off-line pool chlorinators. They both function the same and cost the same (usually under $100). But they are installed differently, and they won’t work with every type of pool set up. An inline pool chlorinator is installed directly into the plumbing of your pump and filter system. An off-line pool chlorinator, on the other hand, is connected with a tube installed on the side of the filter system.

You’ll need to select the automatic pool chlorinator that will fit into your filtration system. Some of these chlorinators can be used in both inground and above ground pools, while other models are specific to one or the other.

Inline Automatic Chlorinator and Off-Line Automatic Chlorinator

Inline Pool Chlorinator

An inline chlorinator is connected directly to your filtration system, after the filter or heater, and before the filtered water is returned to the pool. Since it’s chlorinating the water after it’s passed through the filter and heater, it helps protect pool equipment from corrosion.

Inline chlorinators are plumbed into PVC piping. It’s easiest to hard plumb a chlorinator during pool construction or renovation, but it’s possible to cut the PVC pipe and install a chlorinator after the fact.

An inline chlorinator is a sturdier option with fewer parts than an off-line chlorinator. But you might not have enough space to install an inline chlorinator into your pump and filter set up.

Off-line Pool Chlorinator

If you don’t have the space to add an inline chlorinator at the end of your filtration system, you can install an off-line pool chlorinator. An off-line chlorinator is connected through a separate line that bypasses the rest of the filter equipment.

It’s an option for pool owners that still want an automatic pool chlorinator but don’t have enough room to install an inline model. While you won’t need to cut any piping to install, you will still need to cut small holes into your PVC plumbing.

You can only use an off-line chlorinator if you have “hard” PVC piping. If you have soft flexible hosing, which is common in above ground pool plumbing, you won’t be able to use an off-line chlorinator.

Are you still confused about your pool anatomy and your filtration system? Check out our pool maintenance video course for a step-by-step tutorial so you can finally understand the ins and outs of your pool.

Frustrated by adding chemicals and trying to keep your pool clear all the time?

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What is the Best Automatic Pool Chlorinator?

When shopping for a pool chlorinator, first look for the model that’s compatible with your type of filter system and that can handle your pool’s volume. Some chlorinators are made to sanitize 10,000-gallon pools, and others will sanitize up to 40,000 gallons. If you get a chlorinator that’s too small for your pool, the water won’t be completely sanitized, so be sure you choose an appropriate size.

Here’s the pool chlorinator we recommend:

Our Top Pick
Hayward Automatic Pool Chlorinator (Inline)
Buy Now On Amazon
If you click this link and make a purchase, we earn a commission at no additional cost to you.

Whenever buying pool equipment, such as a pool chlorinator, it’s important to look for well-established brand names like Hayward. They make it easier to find replacement parts in the future and they usually come with a manufacturer’s warranty.

What Kind of Chlorine Is Used in a Pool Chlorinator?

Pool chlorinators work best with slow-dissolve trichlor chlorine tablets or pucks. These tablets last longer than liquid chlorine or granules, giving you more time between pool chemical additions. But more importantly, pool chlorinators use water pressure to dissolve chlorine pucks at a steady rate and granular chlorine will dissolve too quickly.

Chlorine pucks or tablets will only dissolve in your chlorinator when your pool pump is running. If your pump is on a timer and turns, your chlorine will not dissolve and therefore it won’t disperse into your pool.

When you first start using your pool chlorinator, check your chlorine tablets’ dissolve rate and test your chlorine levels at least once a week to make sure there’s enough chlorine getting into your pool water.

Our Top Pick
3-Inch Stabilized Chlorine Tablets
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IMPORTANT: Do NOT mix two or more different types or brands of chlorine in your chlorinator at the same time. You could risk an explosion. Stick to one type of chlorine, like trichlor tablets, and the same brand, if possible.

How to Set Your Chlorination Rate

Just like any other chemical, the amount of chlorine you add to your pool will depend on your pool’s volume. You’ll need to know this before you can set the chlorinator’s dispensation rate.

If you don’t already know your pool’s volume, you can use a pool calculator to figure it out. Your pool’s water volume is calculated using your pool’s surface area times your pool’s average depth.

Pool Volume Calculator Click on your pool shape to calculate the volume of water.
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To add chlorine tablets to your chlorinator, be sure to turn the power to your pool pump off first. Then use the chlorinator air vent to release air pressure or remove the chlorinator cap slowly to avoid inhaling chlorine fumes (and wear protective gear, like goggles and a mask). Add the chlorine tablets and then reset the control valve dial to your desired level and turn the pump back on.

You can add as many chlorine tablets as you want. How quickly they dissolve depends on your chlorinator setting, your chlorine demand, and your water flow rate.

When first setting your chlorination rate, start on a lower setting for the first two or three days. Then test your water and increase your chlorination until your free chlorine levels reach between 1 and 3 ppm. Make sure your water chemistry is balanced, including your pH and Alkalinity levels. If you need help balancing your water chemistry, be sure to check out our guide to Basic Pool Chemistry 101.

Is A Pool Chlorinator Worth It?

We definitely think a chlorinator is a worthwhile investment:

On the downside, it may be difficult to initially install. And with any piece of equipment, it requires maintenance over time. It also requires the same type of chlorine tablets every time you use it (mixing different types of chlorine in your chlorinator is dangerous).

But regardless of the upfront cost and hassle of installation, a chlorinator is a great investment for a hands-free (and worry-free) way to keep your pool chlorinated and sanitized. Again, here’s the one we recommend:

Our Top Pick
Hayward Automatic Pool Chlorinator (Inline)
Buy Now On Amazon
If you click this link and make a purchase, we earn a commission at no additional cost to you.

Frequently Asked Questions About Automatic Pool Chlorinators

Looking for more help understanding more about chlorinators? Here are some common questions and answers.

Are pool chlorinators safe?

When used properly, chlorinators are safe to use. But you must take all safety precautions when handling chlorine or chlorine feeders. Turn off your pool pump before opening your chlorinator and wear proper protection, like goggles, gloves, and a mask. Avoid inhaling chlorine fumes when removing the cap or by using your chlorinator’s air vent to release air pressure. Always follow the manufacturer’s instructions (which may differ from these) and never, EVER mix the types of chlorine you use.

Is there an automatic chemical feeder for bromine?

If you have a swimming pool or hot tub that uses bromine, you can use an automatic chemical feeder like a chlorinator (it’s sometimes marketed as a brominator). The only difference is that instead of chlorine tablets, you’ll add bromine tablets to the feeder. If you switch from chlorine tablets to bromine tablets or vice versa, you will need to purchase an entirely new one. Remember, mixing different chemicals like chlorine and bromine can cause a dangerous chemical reaction or explosion.

What is the difference between an Automatic Pool Chlorinator and a Salt Water Chlorinator?

A chlorine generator, also known as a saltwater chlorinator or saltwater generator, creates chlorine from salt and disperses that chlorine into your saltwater pool. Automatic pool chlorinators, also known as automatic chlorine feeders, dispense chlorine from chlorine tablets that are added to the chlorinator.

Do chlorine pools have a chlorinator?

Not all chlorine pools have one already installed. You will either have to manually add chlorine granules or powder directly to your water or add a chlorine tablet to a chlorine floater or directly into your skimmer basket. But pool chlorinators are relatively affordable (usually $100 or less) and make pool maintenance much easier once installed.

Need More Pool Maintenance Help?

Matt Giovanisci is the founder of Swim University® and has been in the pool and spa industry since 1995. Since then, his mission is to make pool and hot tub care easy for everyone. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
Download Our FREE Pool Care Cheat Sheet
This free printable cheat sheet helps keep your inground, above ground, or Intex pool clean and clear without messing with confusing water chemistry.
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