5 Best Pool Chlorine Tablets – Make Swimming Safe!

Last updatedLast updated: September 12, 2021
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One important part of maintaining and caring for your swimming pool is to maintain the right chemical balance of sanitizers, algae-killing, and chemical solutions. This takes lots of trial and error, practice, and headaches. Luckily, there are a few tricks you can try to make caring for your facility easy and simple, one of which is the use of the best pool chlorine tablets. While it is easy to point out this fact, it isn’t easy to choose the right pool chlorine tablets. There are many options on the market, and what is more, they mostly look the same! But do not fret, we are here to help you. In this post, we will consider some of the best options that you can use right now.

In this post, after considering more than 20 options, we will review five of the top options that will keep your pool safe to swim in. From our roundup, the best option we have found is the In The Swim chlorine tablet. This is our number one option for several reasons. First, it has a really good absorption rate, which isn’t too fast or slow. It also comes in an easy-to-open container, but still has child-proof on it. We have provided further information about this product as well as the features of the four other tablets reviewed below.

In writing this article and coming up with this roundup, we considered several features. Some of the features that we considered include type, active ingredient, tablet size, and quantity. In the buying guide provided, we considered each of these factors in more detail. We have also provided a comparison table, detailed reviews of each product and an FAQ section. Read on to find out more.

Top 5 Pool Chlorine Tablets Review 2021


In The SwimEditor’s Choice

  • Type: stabilized
  • Active ingredient: Trichloro-s-triazinetrione
  • Chlorine: 90%
  • Tablet size: 3 in
  • Quantity: 10 lbs, 8 oz. individually wrapped tablets in easy-open bags

Extra features: perfect for floaters or any automatic chlorine feeder

Our number one pick is the In The Swim tablets. These tablets come in an easy-to-open bucket that is still safe to use if you have children in and around the home. The chemicals found in these tablets are quite powerful; hence, it is important that you keep them away from unwanted hands. For added protection, each chlorine tablet is wrapped in a plastic coating which preserves the quality and prevents water intrusion.

The product contains some really powerful chemicals like Trichlor-s-triazinetrione and chlorine. This chemical serves to sanitize the pool. It is remarkably effective against stuff like bacteria and algae, as well as other harmful microorganisms. To use this tablet effectively, you have to use 1 tablet in 10,000 gallons of water for 1 week. You should note that application varies from pool to pool based on certain factors. First, you need to apply them at the right temperature, and since they are stabilized tablets, they have to be exposed to sunlight to be used properly.

These tablets are chemically stabilized and so will not disintegrate in the water while offering maximum performance.

Each of these buckets contains 14 tablets. Therefore, you have enough to last you for a long time without you resorting to buying any new buckets. It works for a pretty long time and dissolves slowly for the maximum effect.

Because of the chemicals contained therein, these tablets will ensure that your pool is free from dirt and germs.

One drawback that I observed is that some of the new tablets are already broken when they arrive.

The fact that the benefits greatly overshadow the flaws, make In The Swim 3-inch chlorine Tablets an ideal pool sanitizer. They provide first-rate cleansing while efficiently purifying pool of pollutants and eliminating the odor. The tablets dissolve gradually and last long enough for the chlorine to perform its action.

What makes it special?

  • Chemically stabilized
  • Waterproof packing
  • Regulates pH value
  • Superior cleansing action

What cons did we find?

  • Some tablets are already broken

Clorox Pool&Spa Active99Best Value

  • Type: stabilized
  • Active ingredient: Trichloro-s-triazinetrione
  • Chlorine: 90%
  • Tablet size: 3 in
  • Quantity: 5 lbs, 10 x 8 oz. tablets

Extra features: skimmer, feeder or floater applications, long lasting sunlight protection

Up next is the Clorox Pool&Spa chlorine tablets. Clorox Pool&Spa is popular in the pool sanitizing industry.

One of the company’s most popular products is the 3-inch chlorine tablet pack. These tablets are available in a variety of sizes and weights ranging from 5-pounds to 35-pounds and come in a decent packing.

The tablets promise durable action against disease-causing agents as well as algae and slime that pollute the pool. Clorox Pool&Spa Active99 3″ Chlorinating Tablets comes with an active 4-in-1 formula that, apart from killing bacteria, also eliminates algae and keeps the water purified and crystal-clear.

The tablets, like every other top quality product, are UV stabilized and provide first-rate performance while not disintegrating under the sun.

Therefore, you get long-lasting and effective results against the disinfectants. Using only two tablets per week is sufficient to maintain pH levels.

These tablets provide active algae control that sweeps away any organic substances and cleanses the pool while giving a fresh and clearer look. It also prevents further algae growth in your swimming pool and saves you from the trouble of manually scrubbing or cleaning the dirt.

The tablets are placed inside a tightly enclosed container that prevents the heat of the sun while protecting the tablets inside. The container also shields the tablets from moist air to preserve the original quality and effectiveness.

Each tablet comes in a separate wrapping making it highly convenient to use in skimmers, floaters, and chlorinators. You and your family will love its durable performance, protection from disinfectants and waterborne diseases to let you enjoy more time in the pool.

As compared to other such tablets in the market, these tablets often show extreme acidic behavior and may ruin your water and pH balance. Furthermore, they also react strongly with a chemical reaction when used in feeders and the resulting fumes can be highly acidic and dangerous.

These tablets are highly-priced as compared to a lot of its competitors in the market.

Overall, its superb pool cleansing properties will leave you with crystal clear water without any slime or algae.

What stands out?

  • Easy to use
  • Durable against microorganisms
  • Impressive cleansing properties

What cons did we manage to find?

  • Expensive
  • Extremely acidic

Kem-Tek 2815-6Budget Pick

  • Type: not specified
  • Active ingredient: Trichloro-s-triazinetrione
  • Chlorine: 85%
  • Tablet size: 1 in
  • Quantity: 1.5 lbs, 50 x 0.5 oz. tablets

Extra features: UV resistant, suitable for floaters and feeders, slow dissolving, salt system compatible

These tablets are stabilized to minimize chlorine loss to the UV rays. They are made to resist disintegrating, and they contain 85.5% active chlorine and 95% Trichloro-s-triazinetrione. The tabs come in one-inch size but are very effective in maintaining steady and strong chlorine level for your facility.

The best thing about these products is that they are very easy to fill to your chlorinators or floaters. For hot tube fanatics, these are the best tabs since they are very convenient and fit well in smaller floaters. They are also perfect for inflatable or above ground swimming pools.

Overall though, these tablets are a decent pool sanitizing product that lets you make the most of your pool without exerting many efforts. It has a durable performance against harmful microorganisms such as bacteria, viruses, pathogens, and other waterborne diseases.

What do we love it for?

  • They are perfect for small pools.
  • They don’t decay easily.
  • They offer value for your money.

What were we disappointed with?

  • Not great for hot tubs

hth Pool SanitizerBest for Salt Pools

  • Type: not specified
  • Active ingredient: Trichloro-s-triazinetrione
  • Chlorine: 84%
  • Tablet size: 1 in
  • Quantity: 5 lbs, 160 x 0.5 oz. tablets

Extra features: skimmer, feeder or floater applications, long lasting sunlight protection, compatible with salt pools

HTH chlorinating tablets are designed to keep your pool water clean and kill bacteria and algae. 1 tablet can treat up to 10, 000 gallons of water for up to a week. The tablets are sun protected to enhance their durability and effectiveness. You can toss them into the pool directly or place them in a skimmer, feeder or floater.

It comes with active ingredients that are designed to get rid of algae and other microorganisms that can be harmful to swimmers. Furthermore, as one tablet can serve a relatively large body of water, you can rest assured that you will get plenty of use from each pack that you purchase.

As with most tablet products on the market, these tablets are so easy to use. All you need is to throw it in the water, and it will dissolve itself and spread all over the pool.

HTH chlorinating tablets help maintain a chlorine residual of 1- 4ppm, which is pretty cool. One tablet per 10,000 gallons of water is required to maintain clean pool water.

Why did it make our list?

  • Kills bacteria, algae, and other harmful organisms
  • Sun protected to prevent chlorine loss
  • Easy to use
  • Less quantity of tablets is required

What is not ideal about it?

  • The tablets have a sharp bleach odor

Doheny'sBest USA Product

  • Type: stabilized
  • Active ingredient: Trichloro-s-triazinetrione
  • Chlorine: 90%
  • Tablet size: 3 in
  • Quantity: 5 lbs, 55 x 8 oz. individually wrapped tablets

Extra features: made in USA, UV protected, child proof locking lids

Therefore, you get long pool protection that can sustain the entire season. You also do not need to add any extra amounts of the tablet for chlorination since the Sun won’t affect the previous shift.

The tablet’s active ingredients provide all-rounded performance while maintaining the pH and chlorine levels of the water. So, you don’t need any extra chemicals to further add in the pool. These tablets alone are enough to get you the desired result. This saves you money, time and energy.

Another notable benefit that these tablets offer is their reasonable economical cost. The tablets provide the same durable action as other high-end brands tablets but in a less price which is inexpensive to some extent. This increases cost-effectiveness while fetching good results as required.

Doheny’s 3 Inch Swimming Pool Chlorine Tablets offers active cleaning and first-rate sanitizing while getting rid of all disease-causing agent like bacteria, viruses, pathogens, and other germs. This keeps the pool water healthy to swim in.

Furthermore, they cleanse the water from pollutants like algae, slime, scum, and dirt, making the water clear and fresh. Not to forget, each tablet in the package is wrapped separately for added convenience.

As with some of the products reviewed so far, a very prominent and concerning the disadvantage that these tablets hold is the broken tablets. The new packages received contain a lot of broken tablets whose numbers are alarming. This can make them ineffective to use, especially with chlorinators.

Overall, these tablets easily fulfil the basic necessity of sanitizing the water along with cleansing the pool of algae and slime. For the same reason, these tablets are widely used among the audience and are easily available in the market.

What are its best features?

  • Durable performance
  • Thoroughly cleanses the pool
  • Good for outdoor pools

What could be improved?

  • Often come crushed

Things to Consider

In the roundup above, we considered 5 of the best chlorine tablets for your pool right now. In this section, we will consider some of the important parameters that can affect your buying choice.

Types of Chlorine Tablets

On the market right now, you will find two main types of chlorine tablets. These are the stabilized chlorine tablets and the un-stabilized chlorine tablets. 

Stabilized chlorine tablets are great for your outdoor swimming pool. On the other hand, un-stabilized chlorine tablets are good for your indoor pools.

Why is this so? Well, stabilized chlorine tablets last longer in water than the un-stabilized chlorine tablets. Why? Well, stabilized tablets have been exposed to sunlight, and due to this, they tend to clean up the water bodies more thoroughly. For these types of tablets, the more sunlight they are exposed to, the better their efficacy.

Un-stabilized tablets are not great when exposed to sunlight. As a matter of fact, their power even diminishes in such situations.

Why Chlorine Tablets are better than other Chlorine forms

There are several reasons why using chlorine tablets is better than using other forms of chlorine, e.g., liquid or powder. In this section, we will consider these reasons.


From our testing and reviews, chlorine tablets are quite cheap and come in large packages. Therefore, they can last you for a long time. With these tablets, you do not need to frequently purchase chlorine to apply to your pool. Just imagine the money and time this will save you.

Ease of Use

5 Best Pool Chlorine Tablets - Make Swimming Safe!These products are super-easy to use. Unlike powder form where you have to sprinkle the powder or liquid where you have to apply it all around the pool, with tablets you just drop them in the pool and they sort themselves out, so to speak. They spread over the pool automatically, and this saves you plenty of time and effort. All the product above are easy to use, including the hth Pool Sanitizer reviewed above.

Easy to monitor and measure out

While applying chlorine to your pool, there is the possibility of overdoing it and totally upsetting the pH balance. Fortunately for you, this is not an issue when you use chlorine tablets. Since they come in tablet form, you can easily measure out the amount that your pool will require. You don’t have to weigh or mix anything; they are ready-made. All that is required on your part is to select the right number of tablets to put inside the pool, and you are good to go.

Highly versatile

Chlorine tablets can be used in different things, ranging from pools to spas and Jacuzzis.

While chlorine tablets come with all these good advantages, they also come with drawbacks. Let’s see some of these.

Disadvantages of Chlorine Tablets

  • If chlorine tablets come in direct contact with your skin, it can cause allergies, itching and discomfort
  • You should avoid using chlorine tablets with a chlorinator because this produces fumes that are toxic and can even kill.
  • If you use too much chlorine in the pool, it can damage parts of the pool. These include the pipes and lining.
  • Chlorine tablets, when used wrongly, can affect breathing since it releases harmful gases into the water.

Who should use Chlorine Tablets?

Pool chlorine tablets are a popular selection by swimmers and pool owners who know their worth. It is recommended for all type of people that are conscious of their pool safety and purity.

Apart from swimming pools, these tablets also work well with the Jacuzzis, so if you own a hotel and want to present clean and clear Jacuzzis to your customers, then these tablets are for you.

Features to Consider

Before making a purchase you should always consider the following features:

Types of Chlorine Tabs

We have already looked at the two types of tabs. We only need to add that these products are found on either tablets or sticks. Sticks are ideal for outdoor pools and are bigger while tablets work better in chlorinators. So, don’t be confused about which one to buy.

Dosage and Size

There are two sizes of chlorine tabs: 1 inch and 3 inches. The size you will use will depend on the size and type of your dispenser as well as the volume of your swimming pool. A dispenser might hold just one tab or more than one. The Kem-Tek 2815-6 comes in a tablet size of 1 inch.

The number of tabs required per 10K gallons of water is usually shown on the label or in the instructions. Follow these instructions to know the right dosage for your pool.

5 Best Pool Chlorine Tablets - Make Swimming Safe!Package of the Tabs

You might want to chlorinate your facility every week. To save money and time, you should purchase these products in bulk and even buy buckets.

Percentage of Chlorine

Trichlor tabs will offer up to 90% of chlorine. This means that they have more chlorine, and hence, you need fewer products to treat your pool. Most of the products we reviewed above, from In The Swim to Clorox Pool&Spa Active99 come with at least 90% chlorine content.

Stabilized Chlorine Tabs

This means that the product will contain an additive known as Cyanuric Acid that will protect it from sunlight. Our top pick, the In The Swim tablets come with this feature.

How to Use Chlorine Tablets

A really basic question that compels you to wonder why we can’t just throw them in the pool and let them do what they are supposed to.

However, the fact is that simply leaving them on the floor of the pool is the least effective method of using them. They will dissolve more slowly and emit the chlorine unevenly. This way, most of the sanitizer gets wasted, and you’ll need to use even more of it. Also, leaving them on the floor of the pool for a long time can leave behind stains to the material.

Therefore, to avoid that, there are other more, better ways of doing so.

5 Best Pool Chlorine Tablets - Make Swimming Safe!Skimmer

The pool skimmer’s primary purpose is to block out external pollutants like bugs, leaves, and other particles. However, it is a great way to chlorinating the pool water as well. You need to place the tablets in the skimmer. The water constantly runs through the skimmer before going into the pool. Therefore, the chlorine automatically gets dissolved, leaving you with sanitized water.


A floater is a plastic container that can float on the surface of the water. All you need to do is to place some chlorine tablets in the floater and leave it in the pool. The floater itself floats around the pool while slowly dissolving the tablets and releasing the chlorine into the water.


A chlorinator gives you complete control over the amount of chlorine to be added in the water along with the rate at which the chlorine dissolves. It works along with the filtration system of the pool where the tablets are placed in the feeder that eventually releases the chlorine into the water.

What then is the best way to apply Chlorine Tablets?

5 Best Pool Chlorine Tablets - Make Swimming Safe!A chlorinator usually works with your existing pump and filters and can be installed pretty easily. The best thing about using an automatic chlorinator is that it will ensure even distribution of chlorine across the entire body of water.

The only downside is that it can be a little expensive.

However, if you don’t want to invest too much money, you can get a floating chlorinator. It is just a plastic vessel that keeps floating in the pool and releases chlorine into the water.

Not as effective as a chlorinator, the floating chlorinators are extremely cheap and can be found at your local stores.

If you don’t want to spend any money at all, you can just drop the tablets into your pool water directly. Just make sure that you drop them next to the point of water return. This can avoid any damage to your pool’s circulation equipment.

Chlorine Tablets Safety Guidelines

Since chlorine tablets contain an assortment of chemicals, due diligence is required for proper storage and usage.

Store the tablets in a cool, dry and ventilated place. Remember, exposure of chlorine to bleach or even liquid chlorine can result in the release of harmful gases, even explosion. Likewise, contact with moisture or dirt can minimize the potency of chlorine tablets.

As long as you can make sure that chlorine tablets are properly packed and stored, they don’t pose any harm. Here are a few things to keep in mind for further safety:

  • Store out of reach of children and pets
  • Chlorine can be poisonous, so don’t ingest chlorine tablets
  • If you see chlorine fumes coming out of tablets, take them outdoors and avoid inhaling the fumes
  • Use gloves to touch any type of chlorine
  • Don’t mix with any other chemicals
  • Don’t mix with other types of chlorine


This can be a trick question depending on the size of your pool, how much debris you get, and the type of your pool (i.e., indoor vs outdoor, in-ground vs above ground).

Normally, the right number of chlorine tablets depends on the number of gallons of water in your pool. As a rule of thumb, it is ideal to add one tablet for every 5000 gallons.

One thing you need to make sure is to round off the number of gallons to the next 5000. For example, if your pool contains 15,000 gallons of water, consider adding 3 tablets. Likewise, if your pool is 20000 gallons, you will need to add four tablets. If your pool is 16000 gallons, you need to add four tablets. The Doheny’s chlorine tablets, for example, are 5 lbs, 55 x 8 oz. individually wrapped tablets.

Most experts agree that chlorination should be done in the evening or at night. The simple reason is that chlorine will have more time to work and kill the bacteria and viruses in the absence of sun.

Fair enough, the stabilized chlorine can offer some shield against the harsh sun rays, but it does not block them completely. This is why it’s ideal to add your chlorine tablets to the pool at night. However, in case you have an indoor pool, you can chlorinate any time of the day.

The primary ingredient of these products is calcium hypochlorite which is often used in treating water to disinfect it in swimming pools. The tabs also feature Cyanuric Acid, so ensure that you check its levels before you buy the tablets.

Chlorine tabs dissolve in your pool’s water and then make it acidic. This acid, light acid, interacts with bacteria and algae and sanitize your facility surfaces and water.

There are some interconnected features to consider that make a good chlorine tablet. They have to do with absorption rates (how fast it dissolves), how well it kills bacteria and prevents algae, and how breakable the tabs are.

Our Verdict

The roundup and the guide above gives you necessary tips to help you to choose the right pool chlorine tablet. We recommend all, but especially our first three products. The In The Swim tablets are packed with active sanitizing ingredients that battle the disinfectants and eliminate them. Due to their high-end cleansing abilities that make your pool dirt and germ-free, most people prefer it as the best chlorine tablets for the swimming pool. Next are the Clorox Pool&Spa Active99 tablets that are available in a variety of sizes and weights ranging from 5-pounds to 35-pounds and come in a decent packing. The tablets promise durable action against disease-causing agents as well as algae and slime that pollute the pool. The tablets, like every other top quality product, are UV stabilized and provide first-rate performance while not disintegrating under the sun. Lastly, the Kem-Tek 2815-6 are our budget pick. These tablets are stabilized to minimize chlorine loss to the UV rays. They are made to resist disintegrating, and they contain 85.5% active chlorine and 95% Trichloro-s-triazinetrione. The tabs come in one-inch size but are very effective in maintaining steady and strong chlorine level for your swimming pool.

We hope that this review and guide will help you in choosing the best pool chlorine tablets on the market right now.

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