Basics of Automatic Pool Chlorinators: How They Work, Pros, Cons, Types & More

Written by Michael Dean
November 9, 2023

automatic pool chlorinator next to a swimming pool

Proper maintenance of a pool can be a lot of work, so every little bit of help comes in handy! To lessen your workload, I highly recommend an automatic pool chlorinator to help you keep the proper chemical balance in your pool and make it safe for swimming. But are they worth it, and why should you use it?

Below, I walk through how chlorinators work, the different types you can choose from, the pros, cons, and more.

Main Takeaways

  • To regulate the amount of chlorine in a pool, many pool owners use an automatic chlorinator.
  • There are two types of automatic chlorinators: inline and offline.
  • Some automatic pool chlorinator brands are: Hayward, Pentair, Sani-King, and CMP.
  • Automatic pool chlorinators can prevent staining on your pool lining, allow you to set the chlorination levels automatically, and works even when you are not at home. However, it is more expensive and requires regular upkeep and maintenance.

Why Use a Chlorinator in Your Pool?

While some people try to keep their pool chlorine-free, I don’t recommend it. Chlorine helps to kill water-borne germs that often make swimmers sick with ailments such as diarrhea, ear infections, and various skin infections. While chlorine is not the only way to disinfect a pool, it is a tried and true method that will cover the basic threats to your pool’s cleanliness.

The key to using a safe amount of chlorine is to regulate it using an automatic chlorinator. Maintaining the appropriate chlorine level keeps the chemicals from building up and causing skin irritation, eye redness, or other unpleasant side effects.

While you shouldn’t be ingesting large amounts of chlorinated pool water, it’s worth noting that excess chlorine can be caustic to your insides, too. Over time, exposure can also harm your body systems, whether you’re taking splashes to the face or soaking in the pool for hours.

It is essential to keep your chlorine levels between 1.0 and 3.0 parts per million to maintain a clean and well-balanced swim environment.

To keep your pool running optimally, you will need an automatic pool chlorinator to make your life a little easier. Choosing a chlorination method for your pool is not as easy as going and grabbing the first one that looks good. You need to know a few things before choosing a pool chlorinator, so I have added some information below to make it a little easier for you to decide.

What is a Chlorinator and How Do They Work?

While there are other ways to add chlorine to your pool, such as using pool chlorine tablets or an approved liquid chlorine method, an automatic pool chlorinator makes your job much easier. An automatic pool chlorinator is a handy piece of equipment that automatically dispenses the proper amount of chlorine into your pool at the right time, so you don’t have to worry about measuring chlorine or figuring out how often to add chlorine to your pool.

Using an automatic chlorinator is pretty straightforward, but you will need to know how to do it properly so that your pool is getting the right amount of chlorine for its size. You plug your automatic chlorinator right into the pump and pool filter system; from there, it cleans the water returning to your pool.

Types of Pool Chlorinators

There are two different types of automatic chlorinators, inline and offline. Both cost about the same and work much the same, as well. The big difference is how they are installed. To find out which is right for you, we’ve included some details below. Check out my guide on salt water chlorine generators if you have a salt water pool.

Inline Chlorinator


  1. Pool filter
  2. Control valve
  3. Automatic chlorinator
  4. The return to your pool

An inline chlorinator is plumbed into the PVC pipe. Water passes through the chlorinator, dissolving some chlorine tablets and dispersing the appropriate amount needed into the water. For inline chlorinators, you will want to have this hard plumbed in when your pool is constructed or during a pool renovation so that getting to the PVC for cutting is not a huge undertaking.

The inline chlorinator makes it a much sturdier option and has fewer parts to replace. It’s way better bang for your buck and well worth looking into.

Offline Chlorinator


  1. Pipe from your pool pump to filter
  2. Connecting tube
  3. Pool filter
  4. Automatic chlorinator
  5. The return to your pool
  6. Connecting tube
  7. Control valve

If you already have an existing pool and massive construction isn’t an option, then an offline pool chlorinator is the option you want to go with. You will not need to cut a piece of the pipe with an offline chlorinator. Instead, you will only need to put small holes in the PVC plumbing. An offline chlorinator is a good option when there is little room left to install the chlorinator.

Automatic Pool Chlorinator vs. Automatic Chemical Feeder

Automatic chemical feeders are similar to automatic chlorinators. A chemical feeder typically works with chlorine and bromine, whereas chlorinators only work with chlorine.

Automatic Pool Chlorinator Brands

There are several different types of pool chlorinators to choose from, varying in size, functionality, and installation techniques. A few brands to look into are:

Hayward Chlorinators

There are various sizes available in this chlorinator, both inline and offline, so the choice is there for most sizes of residential pools, whether you have an inground pool or above ground pool. The 9lb tablet capacity puts it in the top rankings for larger residential pools.

Hayward CL200 In-line Automatic Chemical Feeder

Hayward makes a great basic automatic chemical feeder that I recommend for most pool owners.

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Pentair Chlorinators

The Pentair chlorinator provides quality performance to keep your pool clean, as they are built with flow-through circulation for maximum quality output.

Sani-King Chlorinators

Double unions make removal easy for storage and cleaning. Various sizes of chlorinators allow you to find an option right for your pool and your needs.

CMP Chlorinators

It has a clear top that makes it easy to check the tablet levels. There is also a flow level monitor on the side of the device for your convenience.

Pros and Cons of Automatic Chlorinators

Of course, you can always take the time to go around your pool and add chlorine tablets along the edges. But an automatic pool chlorinator is a much easier way to ensure your pool’s sanitary needs. There are a few pros and cons to using automatic pool chlorinators, and we’ve listed them so that you may better decide which route to go.


  • Prevents staining of chlorine tablets on your pool lining
  • You can set the chlorination levels automatically
  • Option to install offline or inline
  • It can be used on both above ground and inground pools
  • Works even when you are away from home


  • The cost will set you back more than adding tablets yourself
  • Requires upkeep and may need repair over time
  • Installation may be complicated if your pool is pre-existing

How To Choose A Chlorinator

You must consider the following when you are choosing a pool chlorinator so that it works effectively to sanitize your pool:

  1. Take the size of your pool into account, as you will need a chlorinator that can service the amount of water the pool holds.
  2. Decide on a budget before you begin to look, so you know a price point going in.
  3. Consider the accessories the chlorinators come with, as that will affect installation. These sizes of pool chlorinators also vary greatly, so you will want to know the space you will need for installation.

What Type of Chlorine to Use in a Pool Chlorinator

You can use various chlorine forms in a pool chlorinator: chlorine tablet, stick, liquid chlorine, or granules.

For an automatic pool chlorinator, you will most likely want to use a chlorine tablet or stick as these need to be changed less frequently than liquid chlorine, giving you more time between upkeep.

It is also worth noting a chlorine tablet on your hands may cause a reaction and be unpleasant in general. I include this as a small but significant reason for choosing an automatic chlorinator.

How to Set Your Chlorinator Rate

For your pool to reap the benefits of a pool chlorinator, you will need to know how to set chlorine levels. You need to take a few steps to set your chlorinator rate properly.

  1. To set your chlorinator rate, you must know your pool volume to release the correct amount of chemicals into the water. For this, you will want to ensure that you have bought the right chlorinator for your pool size. If you do not know your pool size, you can figure it out relatively quickly using my pool volume calculator.
  2. Once you are sure that you have the correct chlorinator size, I recommend setting the output at 50% for two to three days and seeing the chlorine levels in your pool. Test the levels to see how clean the water is or if there need to be adjustments. From there, you can adjust the setting according to what your pool needs.
  3. You want your chlorine levels to be one to three parts per million. You can then adjust according to the levels. If the chlorine levels are too high – lower the percentage. If the chlorine levels are too low – increase the percentage. It’s an easy thing to do. Just keep an eye on the levels consistently over time to ensure your chlorinator is still working to its full ability.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Final Thoughts

It’s important to remember that while an automatic pool chlorinator is a bit of a financial investment, in the long run, it will save you a ton of time on pool maintenance and allow you to spend more time enjoying your fresh, perfectly balanced pool. There is also the benefit of not smelling like chlorine after dropping tablets into your pool. Plus, an automatic chlorinator is worth the up-front investment when it comes to saving time.

Questions? Let me know!

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