How To Choose The Best Chlorine Tablets For Your Pool


If you've been using granular or liquid chlorine for your pool, you might be wondering if you should make the switch to tablets. 

Or, if this is your first time buying sanitizer for your new pool, maybe you're wondering where to start.

Either way, let’s take a closer look at how you can choose the best chlorine tablets and then you can be the judge!

How does chlorine work?

First of all, you have to know the importance of using chlorine.

There are other sanitizers that get the job done, but none do it as well as good ol’ inexpensive chlorine.

Chlorine is proven to be the best chemical for killing bacteria, viruses and algae, and that, my friend, is everything you want dead in your pool!

Chlorine works because of a chemical reaction that takes place once it comes in contact with microorganisms and bacteria.

It breaks down into several different chemicals like hypochlorous acid (HOCI) that kills those unwanted pests by destructuring the cells that create them.

The process is called oxidation, which is why some pool owners add more oxidizer to the water when using chemicals that don’t do the job well.

Chlorine only does its job, however, if all the other pool chemistry levels are balanced. 

For example, if the pH level is too high, it will block some of the HOCI, leaving the pool less than optimally oxidized.

So, for chlorine to do its job well, all levels including pH, alkalinity, cyanuric acid, calcium hardness and chlorine need to be within normal ranges, which are:

  • pH: 7.4 - 7.6
  • Chlorine: 1.0 - 3.0 ppm
  • Total alkalinity: 80 - 140 ppm
  • Calcium hardness: 200 - 400 
  • Cyanuric acid: 25 - 50 ppm

Types of chlorine

First of all, let’s explore some of the science-y basics of chlorine.

The different types of chlorine are: lithium hypochlorite, trichlor, dichlor, sodium hypochlorite, and calcium hypochlorite.

And each of them serves its own purpose, although most people just pick up whatever is available at the local pool store and call it good.  

Most of the time, that’s probably okay, but in some instances, one is better than another.

For example, if you happen to have hard water where you live (or water with high calcium hardness), sodium hypochlorite works best because it contains only about 10-12% chlorine. 

This usually has to be used with additional sanitizer, however, to be effective at killing algae or other bacteria.

Calcium hypochlorite, or cal-hypo, is the most commonly used chlorine for pools because it is safe and easy to use. It is also very effective, containing about 65% chlorine.

What most of these have in common is that they're considered unstable, which means they don’t have anything to protect them from being quickly gobbled up by the sun’s UV rays.

That is except for trichlor and dichlor, which are are concentrations of chlorine that contain cyanuric acid (CYA). 

CYA is what's known as a conditioner or pool stabilizer because it protects the chlorine molecules from being destroyed too quickly by the sun. 

Most chlorine tablets you can buy are trichlor tablets, which are effective for most all water types.

Why tablets?

But why tablets?

Most of the time, pool-owners who use tablets instead of liquid or granular chlorine are simply doing it for the convenience.

Instead of having to measure anything out, you just need to know your pool size and drop the tablets in.

One 3-inch tablet will sanitize about 5,000 gallons of water. So if you have a 20,000 gallon pool, two tablets will do the trick. 

There is also the factor of safer handling.

Liquid chlorine can be somewhat dangerous to handle if you’re not careful, causing skin burns or irritation.

But tablets are pretty safe to handle and in fact, are usually individually wrapped so they don’t have to touch your skin.

They also don’t pose the same spill risk as liquid, making them easier and safer to store. 

Shopping tips

If you decide to go with chlorine tablets as your choice of sanitizing methods, be sure to read the reviews of the product you choose.

While there may not be a whole lot of difference in the chemicals they contain, some are just made with better methods and won’t crumble during shipping. 

They come in one or three inch tablets and it doesn’t matter which size you choose as long as you read the instructions and administer the right amounts.

Some people prefer the larger tablets because they're a little easier to handle, especially if you will be adding them directly to the skimmer.

But some prefer the smaller ones for automatic dispensers because you can fit more in them.

Best chlorine tablets

CLOROX Pool&Spa Active99 3” Chlorinating Tablet, Kills Bacteria & Stops Algae, 35LB

Clorox is a trusted name in sanitizers so you can be sure their pool products well exceed expected standards.

These particular tablets (click here to check the price on Amazon) are 3 inches and come in individually wrapped packages, making them easy and safe to handle and dispense. 

They contain 99% trichlor, which is the strongest concentration available in pool products.

And they come in extra large quantities in resealable containers for convenience.

In The Swim 3 Inch Stabilized Chlorine Tablets for Sanitizing Swimming Pools - Individually Wrapped, Slow Dissolving - 90% Available Chlorine - Tri-Chlor - 50 Pounds

In the Swim is another highly-trusted name in the pool industry, and these 3-inch tablets (click here to check the price on Amazon) contain 99% trichlor with 90% stabilized chlorine. 

They are slow-dissolving so they are made to last longer than other tablets, and they're individually wrapped for safe handling and application, and they come in large or small resealable containers for convenience. 

Clorox® Pool&Spa™ XtraBlue 3” Swimming Pool Chlorinating Tablets, Kills Bacteria & Stops Algae (25 LB)

Another Clorox product, these XtraBlue tablets (click here to check the price on Amazon) are great for pools with hard water. 

These contain a bit more conditioner so that in addition to killing germs, it softens water and lasts longer in sunny conditions.

They're are also 3 inch tablets, but they're not individually wrapped like the others.

Also, you may need to purchase a granular shock with higher chlorine concentration in addition to these tablets to occasionally shock your pool as they don’t contain as much chlorine as other products. 

Rx Clear 1-Inch Stabilized Chlorine Tablets | Use As Bactericide, Algaecide, and Disinfectant in Swimming Pools and Spas | Slow Dissolving and UV Protected | 15 Lbs

These 1-inch tablets from Rx Clear (click here to check the pirce on Amazon) are made with 99% trichlor and 90% available chlorine.

Each tablet is individually packaged for safe handling and storage, and they're stabilized with cyanuric acid for a longer shelf-life and pool-life.

They also have added bactericide, algaecide and disinfectant so you cut down on the amount of chemicals you might normally use. 

Clorox Pool&Spa Small Pool 1' Chlorinating Tablets 1.5 lb

Yep...Clorox does it again with their small-pool chlorine tablet solution (click here to check the price on Amazon). 

These tablets are 1 inch and come in smaller containers in case you don’t want the bulk of storing those large plastic buckets most of them come in.

They're made with the same 99% trichlor as their other tablets and come in a perfect size for hot tubs or small home pools. 

Robelle 1440M-K Chlorine Tabs Pool Sanitizer, 35-Pounds

Robelle’s 5-in-1 tablets (click here to check the price on Amazon) not only sanitize, they also prevent stains, control algae and help descale your pool surfaces and plumbing.

They contain 94% trichlor, which, along with their other properties, make them great for pools in hard water areas.

Because of their multi-purpose blend, you'll be able to cut down on the pool chemicals you have to buy, such as algaecide and pool clarifier

They also come in a large resealable container for convenience and storage. 

Pool Mate 1-1405M Chlorine Tablets 3 Inch, 5-Pounds

These 3-inch tablets from Pool Mate (click here to check the price on Amazon) are also considered all-in-one and contain stabilizer, algaecide, stain inhibitor, clarifier and stain descaler in addition to sanitizer. 

This cuts down on the need to buy and store extra chemicals as well as some added time and energy in maintenance.

They're individually wrapped and come in a resealable container with a handle for easy carrying and storage.

Similar to some of the other products we recommend, this one has about 94% trichlor and 85% available chlorine. 

How to add chlorine tablets to your pool

You might be hoping that the simplicity of the tablets means you can just toss them in and forget them.

Well, this is sort of a good news, bad news situation.

You can throw them right into the water, but then they'll all dissolve pretty quickly, possibly over-chlorinating your pool, which is definitely a bad thing.

Instead, there are a few better methods for dispersing them.

1. Skimmer method

Adding chlorine tablets directly to the pool skimmer is a popular method.

The water runs over the tablets while the filter is running, dissolving and distributing the chemical into the water through the return jets. 

It works pretty well because the tablets dissolve over time as the water moves, rather than constantly dissolving.

The problem, though, is that while the filter is not running, the tablets are still dissolving in the water they're sitting in, causing a high concentration of chlorine in one spot.

If you're not careful about removing these sometimes, it can cause corrosion in your plumbing. 

2. Automatic chlorine dispensers

This method gives you the most control over the amount of chlorine that is dispensed.

Automatic dispensers are great because you can fill it with as many chlorine tablets as it will hold and then set the levels to automatically dispense the right amounts.

In other words, you can select 1-3 ppm and the chlorinator will “decide” when to allow the chemical to be dispersed.

Just test your levels regularly to ensure it's doing its job! 

>>Read: How to choose the best pool test kit

You may have to adjust levels if the chlorine levels are wandering slightly above or below what they’re supposed to be.

3. Floating chlorine dispensers

Floating dispensers are an affordable option to use if you’d rather not stick the tablets right into the skimmer or purchase an automatic chlorinator.

These are little plastic floating baskets that you put the tablets in and they dissolve as the pool water washes over them. 

The problem with these is that they give you very little control over the amount of sanitizer that is released into your pool water.

Because they do just rely on the normal current of the pool water, they don’t always move around as much as necessary, causing the chlorine to be unevenly distributed.

Bottom line

There’s no question that your pool needs a proper sanitizer, but the choice is yours when it comes to they type and form you wish to buy.

Other sanitizers are available, but none do the trick quite like chlorine.

And tablets just happen to be the most convenient form available.

Whatever you choose, just make sure to test your chemicals consistently and adjust your dosage as needed for germ-free swimming.

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