How To Use Chlorine Tablets & Add 3" Tabs To Pool Water

Why Chlorine Tablets are Essential for Pool Safety

Did you know that without proper sanitization, your pool can quickly become a breeding ground for harmful bacteria and algae? Chlorine tablets are one of the most effective ways to keep your pool water clean and safe. Chlorine tablets are a vital part of pool maintenance, ensuring your swimming area remains clean, clear, and, most importantly, safe for swimmers. Let’s explore how chlorine tablets work, why they are important, and how you can use them effectively to maintain the best water quality in your pool.

Chlorine is the most popular pool sanitizer for a reason. It effectively eliminates bacteria, algae, and other harmful microorganisms that can make your pool unsafe. When chlorine is added to the pool, it works as an oxidizer and breaks down the cell walls of bacteria, rendering them harmless. Chlorine tablets make it easier to maintain consistent levels of this powerful sanitizer, ensuring that your pool water remains clean and safe throughout the swimming season.

What’s Living in Your Swimming Pool?

First, let’s consider what’s living in your oasis.

Aside from H2O, your swimming pool water probably has dead bugs, debris, sweat, urine, poop, and various body oils from swimmers. Gross, right? These contaminants are inevitable when it comes to pools. Whether it’s leaves that fall in from nearby trees, insects that land on the water’s surface, or oils and dirt from people enjoying a swim, all these things combine to create a pretty unappealing picture. If left unchecked, they can become a breeding ground for harmful bacteria and algae.

Chlorine from chlorine tablets or liquid kills bacteria, algae, and other organisms living in your pool’s water, tiles, cracks, and crevices. Chlorine acts as a powerful sanitizer by attacking the cell walls of these microorganisms, rendering them harmless. By adding chlorine tablets to your pool regularly, you are ensuring that any unwanted invaders are eliminated, keeping your pool sparkling clean and safe. This slow-release chlorine method provides a consistent chlorine level that is essential for maintaining water safety.

Additionally, chlorine tablets are highly effective because they dissolve slowly and steadily. This means that the chlorine is continuously distributed throughout the pool over time, unlike liquid chlorine, which needs to be added frequently. This steady dissolution ensures that the chlorine levels remain stable, which is key for keeping harmful pathogens at bay.

Liquid Chlorine vs. Chlorine Tablets

Are Liquid and Tablet Chlorine the Same?

Yes and no. Liquid chlorine is generally pure chlorine (sodium hypochlorite) and is effective for sanitizing pools, but it can be tricky to store and measure correctly, which makes it a less popular choice for residential pool owners. Liquid chlorine can degrade quickly when exposed to sunlight, which means frequent additions might be needed. Additionally, it tends to have a high pH and can increase the pH of your pool water, requiring adjustments.

Meanwhile, chlorine tablets are a more stable and convenient option. They are composed of chlorine along with a stabilizing agent, like cyanuric acid, which helps prevent the chlorine from being degraded by sunlight. Chlorine tablets are typically made from trichlor, which contains up to 90% active chlorine, making them highly concentrated and effective. The slow-release nature of tablets ensures steady chlorination, and they are more practical for regular maintenance.

Chlorine tablets contain various other chemicals depending on the brand—read the labels for more information. Stabilizers are beneficial because they make chlorine last longer, meaning you won’t need to add it as frequently. However, because trichlor is acidic, continuous use will lower your pool’s pH and total alkalinity, which requires regular testing and adjustments. Different brands also include other additives like algaecides to further assist with maintaining clean pool water.

Liquid chlorine, on the other hand, doesn’t contain stabilizers and tends to degrade more quickly, especially when exposed to sunlight. This means you need to use liquid chlorine more frequently compared to chlorine tablets. It also requires careful handling, as it is a stronger solution and can affect other chemical balances in your pool. This is why many pool owners opt for chlorine tablets—they are simpler to manage, have a longer shelf life, and provide a steady, reliable release of chlorine.

What’s the Best Pool Chlorine Brand?

For my pool, I prefer Clorox XTRA Blue tablets, but there are a lot of choices, and most are similar in terms of chemical content and price. Other popular brands include In The Swim 3-Inch Chlorine Tablets, which are known for their strong and consistent chlorine output, and HTH Super 3-Inch Chlorinating Tablets, which also contain built-in algaecides to further help with algae control. Comparing these brands can help you find the right fit for your pool, depending on your specific needs and preferences. XTRA Blue seems to do a better job in my pool, controlling algae with fewer tabs per week. This means less frequent dosing and more time for me to enjoy the pool without having to constantly worry about maintenance. The formula includes stabilizers that make it effective against a wide range of contaminants, plus it works to control algae growth very effectively, making it a reliable choice. It’s also worth considering the specific chlorine tablet quantities you need, depending on the size of your pool.

However, choosing the right brand comes down to your preferences and needs. It’s always a good idea to experiment with a few brands to see what works best for your unique pool setup. Some brands may have additional additives, such as clarifiers or algaecides, which can enhance water clarity and further reduce the need for additional chemicals.

Follow a Regular Pool Maintenance Schedule

Without chlorine in your pool, bacteria and algae will take over and turn the pool water green, making it dangerous. It is equally important to maintain proper pH and total alkalinity levels to ensure overall pool safety and the effectiveness of the chlorine.

But this mess can be avoided with regular maintenance. By having a consistent maintenance schedule, you can prevent most of the issues that arise from a lack of chlorine. Pool maintenance is all about consistency; it’s far easier to keep your pool clean and safe than to deal with the consequences of neglect. Proper care will allow you to enjoy your pool without any unexpected surprises, like cloudy water or algae growth.

Here’s the Plan:

Follow a pool maintenance schedule that includes testing the chlorine levels in your swimming pool weekly (when the pool is open). You should also check other key metrics like pH, total alkalinity, and calcium hardness. Maintaining proper chlorine levels is essential for the effectiveness of the sanitizer.

Testing your pool water is critical because it allows you to know exactly how much chlorine is required to maintain optimal levels. This will help keep your pool chemistry results accurate and prevent adding excessive amounts of chlorine tablets at once, which could lead to an imbalance that makes swimming unpleasant. Regular testing helps keep water chemistry balanced and ensures chlorine levels are safe for swimming.

Keeping track of these key factors can be simplified with digital water testers, which allow for quick and precise measurements. By ensuring that pH, alkalinity, and chlorine levels are all in the recommended ranges, you can significantly reduce the likelihood of issues such as green water, cloudy water, or damage to pool equipment. A regular routine of testing and adjusting as needed will keep your pool in pristine condition.

Chlorine Testing

How to Properly Test Your Pool Water

When testing your pool water, get the water sample 10–12 inches below the surface to ensure it is representative of the water throughout the pool. Taking water from the surface might not give an accurate reading, as surface water can be influenced by various elements like evaporation or nearby contaminants.

Another thing to note is to take the sample away from the pool’s edge or against the wall. Water near the edge might contain debris or other particles that could affect the reading.

I know how easy it is to just reach down along the pool’s edge with the test tube, but it’s not a good practice. Always move to the middle of the pool if possible to get the most accurate sample.

Pool Testing Kits

There are several types of pool testing kits available, each with its own pros and cons. Test strips are affordable and easy to use, making them a popular choice for many pool owners. However, they can sometimes be less accurate than other methods. Liquid test kits are more precise and allow you to test for a wider range of chemicals, but they can be more cumbersome to use. Digital testing kits offer the highest accuracy and convenience, but they are typically more expensive upfront. Understanding the differences between these options can help you choose the best kit for your pool maintenance needs.
It’s incredible how many different swimming pool water test kit supplies you can buy to keep track of your chlorine levels. From simple test strips to advanced digital kits, there is a wide variety of options for every pool owner’s needs and budget.

I recommend buying a pool test kit that offers these three different types of test results:

Free Available Chlorine – The free available chlorine is the amount of chlorine in the water available to sanitize. This chlorine test result is the most important because it tells you how much chlorine is left to kill germs.
Combined Chlorine – Combined chlorine measures negative compounds in the water. If this number is high, there’s an indication that the water in the swimming pool has reacted with contaminants, forming byproducts that reduce the chlorine’s effectiveness.
Total Chlorine – Total chlorine is the combination of free and combined results. It provides an overall measure but does not give the details needed to determine how effective your chlorine levels are.

Your pool service schedule should include weekly testing of chlorine and chemicals, adding chlorine tablets or liquids as required, adding shock, running the pump, backwashing, cleaning the pool filters, and brushing. By doing so, you can maintain a balanced and clean swimming pool that’s safe for all users. Make sure to monitor your chlorine tablet quantities carefully and follow the chlorine tablet notes regarding best practices for adding them.

A well-maintained pool should also include shock treatments every two weeks or after heavy use. Shocking the pool involves adding a large dose of chlorine to eliminate bacteria and contaminants that regular chlorination may not handle. This practice helps to “reset” your pool’s chlorine levels and address any buildup of chloramines.

Effects of Chlorine Levels

Low Chlorine Levels

When swimming pool water doesn’t have enough chlorine, swimmers can become ill from the bacteria and algae that may be living in the water. The primary job of chlorine is to kill these harmful organisms, so without enough of it, the pool becomes a risk for everyone. Trichlor tablets are a great way to maintain chlorine levels without frequent adjustments.

Adding chlorine to pool water with low chlorine levels may cause the water to turn cloudy. It’s a good practice to wait until the water clears up before entering it. The cloudiness is a reaction of the living organisms to the chlorine.

If you notice cloudiness, it’s important to test the water and add the appropriate amount of chlorine to bring it back to the correct levels.

Low chlorine levels can lead to algae blooms, which turn your pool water green and make it unsafe for swimming. Algae can grow very quickly if chlorine levels are not kept within the recommended range, especially during hot summer months when water temperatures rise. Keeping a consistent supply of chlorine tablets helps mitigate these risks, ensuring that your pool remains inviting and safe.

High Chlorine Levels

Too much chlorine in a swimming pool can lead to several health issues for swimmers. High chlorine levels can cause skin irritation, resulting in dryness, itching, and even rashes. Swimmers may also experience eye discomfort, such as redness and burning sensations, as the high chlorine content can be particularly harsh on sensitive eye tissues. Additionally, inhaling high levels of chlorine can lead to respiratory issues, including coughing, throat irritation, and in severe cases, difficulty breathing. To safely lower high chlorine levels, you can leave the pool uncovered to allow the chlorine to dissipate naturally under sunlight, reduce chlorine tablet usage, or use a chlorine neutralizer. It is important to monitor chlorine levels regularly to avoid these potential health risks and ensure a safe swimming environment.

Caution! These indications can also mean enough chlorine but too much acid. The only way to know for sure is to test the pool water weekly and adjust your chemicals based on the results.

Watch this interesting Pool Chemistry Video about all the chemicals in pool water…

Swimming Pool Chemistry 101 Transcript

My name is Dr. Russell Betts. I’m the chief scientist here at Goat Chemist. I’m here today to present our next video in the series of video is called pool chemistry 101 your backyard swimming pool is a dangerous chemical cocktail designed to eliminate pathogens from growing or propagating in your pool to make it more pleasant to swim in shall we say but those chemicals are extraordinarily dangerous and it would be nice if there was a safer more convenient alternative to this chemical concoction that we’re throwing into our pool every weekend and maybe in a subsequent video we’ll learn a little bit more about that but for right now let’s learn about the chemical soup in our backyard we all know that chlorine goes into our pools to help eliminate pathogens we all know that but chlorine is really a gas chlorine is cl2 so it’s not really chlorine but it’s a variant of chlorine and there’s two of them that are commonly used the two that are commonly used is called sodium hypochlorite or calcium hypochlorite either one will do either one either one will do the same thing what they’re designed to do basically is kill bacteria and fungus analogy chemically they’ll chemically kill them but keep in mind though chlorine is light-sensitive it’s also heat sensitive the pool chlorine is heat sensitive which means that you have to keep adding it every weekend basically to keep the chlorine levels high enough so that things like bacteria and viruses can be eliminated if the pool if the pool chlorine 4 falls too low things like algae and bacteria will propagate in your pool making it unpleasant to swim in so you got to keep adding these chemicals now the industry has developed another chemical yes one more chemical that will help to protect your chlorine from degradation and that Kevin flow is called sine ARAG acid this is a structure of sine Eric acid right here this designed to help stabilize the coin in your pool it’s called a pool stabilizer all it’s designed to do really is to help prevent the degradation and the heat degradation of your chlorine in your pool that’s all it really does lately or more recently on the market has come another chemical yes one more chemical called trial or tryke lawyers right here trial or as you can see is very similar to cyanuric acid in fact it’s chemically related to it this molecule or chemical can form so they label chloride in your water and cyanuric acid at the same time it’s a much more chemi Windows 98 cal use but it still gives you the same two chemicals you’re not adding less chemicals to your pool.

Best Pool Chlorine Brand

You’re just adding the same amount of chemicals at one time that’s how try Clorox now we all know all of us backyard pool owners know that when you add chlorine to your pool you also have to measure the pH the pH is simply a measurement of acidity the higher the number of the pH they around pH 14 that’s very basic the lower the pH numbers say around pH 1 or 2 that’s very acidic for example the oceans pH is about 8.1 slightly basic a can of coke about 3.5 very acidic your pool wants to be right around 7.4 that’s the optimum pH for sodium hypo chloride to work in order to keep it there you have to add either an acid or a base depending on what your pool pH is so you go to on a Saturday morning take a sample from your pool water find out the pH and your 500 it’s 9 pH 9 that’s way too high you’ve got to bring it down in order to bring the pH down you have to add an acid and there are two commonly used assets in pool chemistry one is muriatic acid which is right here near your attic acid is simply hydrochloric acid it’s a dangerous industrial chemical you have to be trained professional to use it or you could get very hurt there’s a skin hazard you can burn yourself or there is also an inhalation hazard you can burn your lungs if you inhale it it’s very dangerous the industry has responded to that by providing what’s called a dry acid a dry acid is sodium bisulfate sodium bisulfate is another industrial chemical it’s also dangerous in the wrong hands you have to know what you’re doing to use it I’ve got a PhD in chemistry . I’m comfortable using it, but you probably don’t have this. I don’t have the experience of handling Kevin Lister most of your career so it might be a little bit intimidating for you so it really can be dangerous you have to be careful so let’s take for another example you test your pool you’ve added too much acid now your pools acidic you’ve got to bump it back up it’s kind of like we call it here go camels we call it chasing the pH the pH is too high you got to bring it down now it’s too low you got to bring it up kind of frustrating kind of annoying kind of a lot of work to do on a Saturday afternoon if your pool chemistry is too acidic you have to get more basic to do that you add another chemical yep one more chemical this is sodium bicarbonate it’s a very commonly used pool chemical this is baking soda it’s pretty harmless to you but you still have to buy it you still have to throw in your pool and this one’s sodium carbonate sodium Curtis another way to bump your pool pH back up to 7.4 it’s also relatively harmless they’re not dangerous at all but you still have to buy them and you still have to do it keep in mind the pool chemistry must be maintained very specifically in order for it to be effective this does sound like a lot of work this is a lot of work. I was a chemist and would not want to do this on Saturday afternoons when I’d rather play with my children, so let’s think about a more convenient, safer, and more effective way to prevent your pool from growing bacteria or fungus in subsequent videos. I will show you that there is a more effective method. I hope that you’ve enjoyed this video. I want to say again that my name is Russell Bass. I’m the chief scientist here at Go Camelus. I hope you’ve enjoyed this video. Thank you very much.

How to use Chlorine Tablets

Note: Handle Chlorine Tablets with Care

It’s always best to use precautions (eye protection and gloves) when handling chlorine tablets because they are highly concentrated, and the chlorine can be easily absorbed into your skin.

Also, chlorine is bleached and will ruin clothes (think Clorox). If you get it on your clothing, remove the clothing immediately and wash them…

Chlorine tablets may have harmless powder or dust, but the chlorine powder will still cause staining and irritation, so wash hands and clothes immediately.

#1. Comparing Before Buying 3 inch Pool Chlorine Tabs

OK, let’s review different best-selling brands of chlorine tables…

#1 Best Seller

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

Cleaner, Safer Water: Our chlorine tablets remove bacteria, algae, and other organic contaminants to ensure your above ground or inground swimming pool stays clean and clear throughout the entire season
Powerful Sanitization: 99% Trichloro-S-Triazinetrione with 90% stabilized chlorine. Tablets do not expire and are non-perishable, but best used within 2 years of manufacture.
Long-Lasting Protection: Slow-dissolving to ensure consistent chlorination. Perfect for use in floaters or automatic feeders
UV Protected: Sun-stabilized to resist depletion from harmful UV rays
Usage: Ideal size for floaters or automatic feeders

#2 Best Seller

HTH 42052W Pool Care 3" Chlorine Tabs Advanced, Individually Wrapped Tablets - Swimming Pool Sanitizer with Clarifier & Algaecide, Destroys Bacteria & Algae, Delivers Clear Water All Season, 5 lbs

BENEFIT: Sanitizer, clarifier, and algaecide to protect your swimming pool and swimmers with one easy, convenient, and individually wrapped 3-inch tablet
CLEAR BLUE WATER: This advanced formula sanitizes, clarifies, and kills algae for beautiful, clean, and clear water all season
SLOW DISSOLVING, LONG LASTING: Sun protected for longer chlorine life, HTH 3” Individually Wrapped Chlorine Tabs Advanced dissolve slowly and last up to one week
COMPATIBLE WITH ALL POOLS: This product is great for all pool types including vinyl-lined pools and saltwater systems; Use in floater, feeder, or skimmer basket
YOU’RE ALL CLEAR WITH HTH: For best results, use HTH 6-Way Test Strips twice weekly to test and balance your swimming pool water and keep chlorine levels between 1 and 4 ppm

#3 Best Seller

HTH 42049 Pool Care 1" Chlorine Tabs, Swimming Pool Sanitizer with Added Clarifier - Eliminates Bacteria & Algae, Makes Water Clean & Crystal Clear, Sanitizes & Protects - Slow Dissolving, 1.5 lbs

BENEFIT: Protect your swimming pool and enjoy clean, clear water with these easy-to-use chlorine-based tabs; Kills algae and bacteria
CLEAN, CLEAR WATER: HTH Chlorine Tabs keep water clear while protecting against bacteria, algae and other organisms
SLOW DISSOLVING, LONG LASTING: Sun protected for longer chlorine life, HTH Chlorine Tabs dissolve slowly and last up to one week
COMPATIBLE WITH ALL POOLS: This product is great for all pool types, including saltwater systems; Use 1" tabs for above ground pools, 3" tabs for inground pools; Use in floater, feeder, or skimmer basket
YOU’RE ALL CLEAR WITH HTH: For best results, use HTH 6-Way Test Strips twice weekly to test and balance your swimming pool water and keep chlorine levels between 1 and 4 ppm

#4 Best Seller

Clorox Pool&Spa XTRABLUE 3” Chlorinating Tablets, Individually Wrapped, Kills Bacteria & Stops Algae (5 LB)

Cleans Water & Stops Algae: Kills harmful bacteria and prevents equipment corrosion, scale and stains. Kills and prevents all types of swimming pool algae (green, mustard, black)
Long-lasting sunlight protection: Contains chlorine stabilizer to extend the life of your clean
Creates Silky Smooth Feeling Water: XTRABLUE chlorinating tablets contain conditioners for silky smooth feeling water
Usage: Apply 2 tablets weekly to treat 10,000 gallons of water, add more tablets as needed to maintain adequate sanitation. Safe for all swimming pool surfaces, including vinyl, plaster, fiberglass, and tile.
Clorox Pool App: Test like an expert anytime, anywhere with the Clorox Pool App. Solve common swimming pool problems and get personalized product and dosage recommendations

#5 Best Seller

99% Trichloro-S-Triazinetrione with 90% Available Stabilized Chlorine
Stabilized (slow dissolving) Tablets
Tablets are individually wrapped
Excellent for floating feeders, skimmers and automatic chlorinators
50 Pound Bucket of 3" Tablets (IMPORTANT NOTE: Depending on availability, this product may ship as (2) x 25 Pound Buckets.)

#6 Best Seller

PROFELIZ Chlorine Tablets 3 Inch for Swimming Pools, Kills Bacteria and Stops Algae, Slow Dissolving,Exclusive Protective Packaging,Pool Chlorine Tablets,20lbs

[ Exclusive Protective Packaging]: Each 5pcs tablets are tightly wrapped in a protective plastic box to prevent accidental breakage .
[Active Ingredients]:Each chlorine tab contains 99% Trichloro-S-Triazinetrione with 90% available chlorine.
[Clean Effectively]: Kills bacteria and stops algae growth to keep your pool clean and clear all season long.
[Long-Lasting Protection]: Ensure your pool remains effective with Profeliz 3 inch chlorine tablets even under direct sunlight exposure. Profeliz chlorine tabs are designed to dissolve slowly and last up to one week.
[Suitable for all pools] : This product is great for all swimming pool types, including above ground and in-ground pools.Profeliz 3 inch chlorine tabs for swimming pool fit easily into most of pool skimmers, floaters or other chlorinating devices.

#7 Best Seller

Xtremeclear 3" Swimming Pool Chlorine Tablets 99% Pure Tri-Chlor| Long Lasting & Slow Dissolving | Pro-Grade Pool Sanitizer | 5 Pounds Bucket

Active Ingredients - Our pool tablets are pro-grade made from 99% Trichloro-S-Triazinetrione and 90% stabilized chlorine
Ready To Use - Size perfect for floaters, pool skimmer or any automatic feeder which bigger than 3 inch (Floating Tablet Dispenser Sold Separate ASIN: B07193P5HZ)
Saving Money - Having our chlorinating tablets, you don't need change the frequently, 1-tab helps you saving about 5,000 gallons of water
Versatile - The chlorine tabs are perfect for swimming pools, hot tubs, spa, hot spring pools, water parks, even for toilets
Long-Lasting Chlorine Tabs - Each tab is pre-stabilized against the sun's UV rays to prevent premature chlorine burn-off, making them last longer

And just in case you’re wondering, I used to get my chlorine tablets at Lowe’s or Leslie Pool Supplies, but now I buy pool supplies and chlorine tablets online.

#2. How to add chlorine tablets to the pool (Usage):

Chlorine tablets are the most common form of chlorine and are easier to use than liquid. When purchasing chlorine tablets, buy a quality brand and keep them stored in a cool and dry location away from pets and children. Fresh is the best!

Remember it’s not about buying the cheapest or most affordable chlorine tablets…

Below is a chart of how many chlorine tablets to add to your pool water. This chart is for reference only but should help keep your chlorine level close to the correct levels.

#3. How Much Chlorine Should You Add to Your Pool?

3″ Jumbo Tabs / 8oz. PER GALLON OF POOL WATER

Note: For reference only.

Adjust chlorine doses as needed and always read labels.

#4. How to Properly Add Chlorine Tablets to Your Pool

Easy, right?

Congratulations! If you’re a beginner, you’ve learned to use chlorine tablets.

Oh, BTW, you’ll need a chlorine dispenser like the one in the video, but do you know they come in all sizes and designs? I’ve had to replace my dispenser every 3 years because the sun cooks the lid, which eventually breaks. I recommend the one in the image below – it’s heavy-duty.

Conclusion

While chlorine is essential to caring for your swimming pool, it’s dangerous, so you need to be careful and protect yourself when handling it. Chlorine tablets make adding chlorine to your pool easy, but they can be misleading.

A regular DIY pool service schedule includes adding chlorine tablets as needed to maintain the proper level.

Caution! Most test kits advise adding ounces of liquid chlorine rather than tablets so this may take some learning to get used to their affect on your swimming pool. Careful not too much.

If you can’t figure out the best pool chlorine brand, please get professional pool service assistance.

Recommended reading if you’re looking for the best pool chemicals and supplies for your DIY pool care: Swimming Pool Chemicals (Updated Daily)

Product information was last updated on 2025-03-24.

How to Use Chlorine Tablets & Add 3″ Tabs to Pool Water