Different Types of Chlorine

Chlorine and the use of Shock are the basic ingredients for the Control of your pool Chemistry. By mastering your pool, you will save hours of your time and countless amounts of money from failures. What type of Chlorine works best to control your Pool?

The Best Chlorine for you to use daily in your pool & for Shocking: 

Contains over 70% of the active ingredient (AC) Available in Chlorine
Fast Dissolving 
Contain Stabilizer like Cyanuric Acid

99% Active Ingredient-Trichloro-S-Triazinetrione (Trichlor)
Contains Stabilizer

Knowledge is key to controlling your swimming pool this will save you time and money, in the long run, keeping you out of the pool supply store looking for help because you lost control of the chemistry it starts with a strong sanitizer that works well with your pool.


What is the Best Pool Chlorine


Buy the right Chlorine and Super-Chlorinate every week and you will control your swimming pool. You will Master the Art of Keeping a Perfect Pool all through the season and keeping your wallet in your back pocket too.

There are only 5 types of Chlorine:

  1. Sodium hypochlorite
  2. Lithium hypochlorite
  3. Calcium hypochlorite
  4. Trichlor
  5. Dichlor


Sodium Hypochlorite

is liquid Chlorine. It’s between 10-12% Available Chlorine or (AC) as you might read on the label. Available Chlorine is the amount of chlorine that is used to disinfect. The strength or muscle.

Household Bleach is Sodium Hypochlorite but is only around 5% AC Available Chlorine. not very good for disinfecting the pool. It’s normally used in Industrial treatment or large pools at Amusement Parks it’s distributed by Chemical Feeders from large storage containers.

 Calcium Hypochlorite

This is the type of Chlorine that you see in tablet and granular form. Calcium Hypochlorite is approximately 40-78% AC or Available Chlorine. This type of Chlorine is used in daily maintenance as the main way to sanitize your pool and Shock your Swimming Pool.

When you go to the store this type is the likely type of Chlorine that you will see. The only difference in the types of Calcium Chlorite Chlorine that you see will be the AC or strength of it.

 Lithium Hypochlorite 

This type of granular Chlorine is approximately 35% AC but can dissolve super fast. That makes it great for shocking in Vinyl or Fiberglass Pools. It is also good to use if there are problems with the pool having hard water. It is expensive to use and might be better to use in smaller vinyl pools.

Trichlor and Dichlor are types of Chlorine that are approximately 80-90% AC. They are also Stabilized.  Stabilized chlorine has Cyanuric Acid which acts as a type of sunblock for Chlorine. Cyanuric Acid slows the process of the sun breaking down the disinfecting powers of Chlorine.

Therefore, Dichlor and Trichlor are used in outdoor pools as pucks/tablets, sticks, and through the skimmers or through a Chemical Feeder. Because indoor pools do not need to worry about the sun, and do not need Cyanuric Acid, There is no need to worry about this.


How to Shock Your Pool


Chlorine chemistry plays a key role in protecting and helping to keep swimming pools healthy, clean, and safe.

It safely eliminates bacteria, viruses, and parasites from water and ensures lasting disinfection during its time in the pool. When Chlorine is added to the pool for a while at the same dose, bacteria and organic material start to get resistant to its disinfecting power.

So your kids have a pool party the next day you will need to Bump the dose. That just makes sense. Right?  Even if they didn’t you should super-chlorinate every week in the summer months.

Free Chlorine or FAC is the simplest test to monitor and should be monitored every day.  Free Available Chlorine is Chlorine that is the portion of the Chlorine that is leftover in the pool to guard against any contaminants that come their way day.

Free Chlorine levels should always be somewhere between 2-4 ppm. Never below 1.0 ppm

Combined available chlorine (CAC) or chloramines. The portion of chlorine in the water that has reacted and combined with ammonia, nitrogen-containing contaminants, and other organics such as perspiration, urine, and other swimmer waste. Some chloramines can cause eye irritation and chlorine odors. Sound Familiar! When you smell chlorine coming out of your pool it’s not the right type of Chlorine so you need to Bump the dose.  

Total chlorine is the sum of both the free available and combined chlorine. Total Chorine should never go less than 0.2 ppm

Superchlorination is another term that is sometimes used for shock treatment with chlorine products when 5 or more ppm of FAC is added.

This mode of shock treatment in addition to oxidizing undesired wastes is used to rid the pool of algae and bacteria that might be hiding in filters and hard-to-sanitize areas like the nooks and crannies all around the inside of your pool. This little space is where algae and bacteria hide and colonize to where it’s starting to destroy your pool. So how do you avoid this from happening in Shock Your Pool?

Shock treatment. The practice of adding significant amounts of an oxidizing chemical to the water to destroy ammonia, nitrogen-containing, and organic contaminants. Adding chlorine as a shock treatment can also control algae and bacteria, but read the label to make sure that your product can do this.



Do I need to Remove Phosphates from my Swimming Pool Water?

No, It is unlikely that you will be able to remove all phosphate entering your pool:

  • Keep pool chemically balanced
  • Properly sanitized
  • Occasionally add algaecide & fresh H2O
  • Daily skimming
  • Scrubbing pool walls & floors
  • Using a flocculant
  • Then vacuuming
  • This practice will keep phosphate levels at bay at no cost …………………………………………………………………………….. Read more



When the swimming pool’s usage is on a different day today, the temperatures can be extreme. Depending on how hot the week has been and how many people were in the pool will determine how much shock chlorine you’ll be using at the end of the weekend or even at mid-week when your residual testing comes up low.

The best Shock Treatment is fast-dissolving granular Chlorine which is over 70% Available Chlorine. There is a certain percentage of inert material that will find its way to the bottom of your pool. So vacuum the next morning if you can.

Superchlorination or Shock Treatment also gets rid of chloramine odor.

Adding 10 times the level of combined chlorine or chloramines in the water achieves so-called breakpoint chlorination when there is enough extra chlorine to consume the irritating chloramines.

Once Free Chlorine Levels Start to slip, you need to shock your pool. In Fact, Super-chlorinating every week or so during the summer months is highly recommended. In order to prevent a problem, you will be able to offset a bigger problem and this is the first place where you will save money. Lots of it.

Don’t try to save a buck on pool test kits. Always use a reliable kit with fresh reagents that have expiration dates on the bottles before Testing Pool Water.


What is the best Swimming Pool Return Jets Position?

At the Deepest End of the pool
turn the Return Jets (eyeballs) located on the pool walls angled down toward the bottom of the pool at a 45° angle

In the Shallow End of the pool
turn Return Jets clockwise to about 8 o’clock at a 45° angle so the return water to the pool is mixing in a circular motion .……………………………………………………… Read more


With a little bit of knowledge, you’ll know at least the basics of pool care, which will enable you to Master the Art of Pool Operator.

Chlorine is at the tip of the very basic ingredient for that success. Know your chlorine. It all starts right there. It will drive the Chemistry under the right balance to minimize any problems for the season to make you the Master of Your Swimming Pool.


What are some ways Pool Owners can use to Prevent Child Drowning?

  • Use Anti-Entrapment Drain Covers
  • Teach Swimming Skills
  • Install fencing, high Latch Gates, & Pool Alarms.
  • Water Competency & CPR Training
  • Don’t use alcohol in the Pool area
  • Use anti-Slip Mats, Safety Nets & Tie-Off Ropes
  • More Supervision
  • Childproof pool covers ……………………………………………………………………………………………………………………………… Read more

JimGalloway Author/Editor


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