Guide to Using Dichlor Chlorine

Having crystal-clear, refreshing water is what every swimming pool owner wants, but how do you get there?

Learning about the different types of chlorine available can be a challenge for new pool owners, but I can help by bringing you up to speed. You’ll only need to learn about a few different types of chlorine and their advantages and disadvantages. You’ll be a pool pro in no time!

Let’s talk about dichlor chlorine.

What is Dichlor, and How Does it Work?

Dichlor, short for Dichloro-S- Triazinetrione, is one type of chlorine available for keeping pool water clean. Similar to trichlor, a different kind of chlorine, dichlor is usually granular but can also be found in tablets. You can buy dichlor in one-pound bags or in bulk.

With a pH level close to neutral at about 6.5, dichlor can be dissolved in a bucket before adding to your swimming pool or added through the pool skimmer. Other pool owners add dichlor directly to the water.

Dichlor in tablet form can be added through a pool skimmer or an automatic chlorinator.

Dichlor and other types of chlorine sanitize swimming pool water through a chemical reaction.

When dichlor reaches your pool water, it changes into hydrochloric acid. Free chlorine, or hypochlorite ions, from this reaction latch onto bacteria and other impurities. They then create chloramines and destroy the bacteria in the process. As the water is sanitized, chloramines build up until they turn into gas.

Pros and Cons of Dichlor

When you’re picking the chlorine you’ll use to sanitize your pool water, it’s essential to know the advantages and disadvantages of your choices. Here are what I think are the major pros and cons of sanitizing your water with dichlor.


First, here are the pluses of using dichlor chlorine to sanitize your swimming pool water, and there are several to consider.

Dissolves Quickly

Dichlor will save you time if you pre-dissolve since it dissolves in water quickly. If you add dichlor into water directly, this is also a plus.

High in Stabilizer

Dichlor has a high level of cyanuric acid, commonly known as a stabilizer. If your pool tends to have lower cyanuric acid levels, dichlor could be a way to fix that while also adding chlorine.

No Big Changes to Pool pH

Dichlor won’t significantly impact the pH of your pool water since it is nearly neutral. It will still give you a slight drop in pH since chlorine changes into acid when it reacts to water.

Easy to Purchase

Dichlor, whether in granules or tablets, is easy to buy online or in pool-supply stores in your area, although the tablets aren’t as easy to find as granular dichlor. Dichlor can be purchased in bulk as well as in bags as small as one pound.

Stores Well

Don’t worry if you have plenty of dichlor left at the end of summer. Dichlor has a long shelf life, so that’s why many pool owners buy it in bulk. Just be sure to store it unopened. Contamination is a danger with an open bag or tub of dichlor.


Dichlor has a few disadvantages, including some significant ones. Don’t choose dichlor or any pool chemicals without first knowing the cons.

Handle with Care

Dichlor is volatile and can explode when mixed with the wrong chemicals, even in small amounts. Mixing dichlor with even the residue of calcium hypochlorite can result in injuries. For safety, don’t store opened packages of dichlor because of the risk of contamination. If you buy it in one-pound bags, use the whole bag.

Must Be Added Manually

Dichlor chlorine can’t be added via drip-feed as other types of chlorine, such as trichlor tablets. This means additional work for you, the pool owner. Automated choices might make your pool maintenance easier.

Priced Higher Than Some Types of Chlorine

Dichlor isn’t the most expensive form of chlorine, but it is more expensive than some choices. For example, dichlor granules are nearly twice the cost of trichlor tablets, pound for pound.

When You Should Use Dichlor

Cyanuric acid, often called stabilizer, is used in pools that are exposed to the sun. Dichlor chlorine is high in cyanuric acid, so if your swimming pool’s water is low in cyanuric acid, adding dichlor is a simple way to bring your pool’s acidity up while also adding needed chlorine.

When You Shouldn’t Use Dichlor

If you have too much cyanuric acid in your swimming pool, the chlorine will not work as efficiently in sanitizing your pool water. If your pool water tends to be high in cyanuric acid, then adding dichlor would not be advisable. You would have to add more chlorine to offset the cyanuric acid, resulting in a need for more chlorine, a cycle of inefficiency.

Suppose this is a problem during regular chlorination. In that case, it will be an even larger problem if you are shocking your pool by adding ten times the level of free chlorine to combined chlorine to remove chloramines from your water. Removing a chloramine buildup will prevent irritation and boost chlorine efficiency.

Dichlor would only be a good option for shocking your pool if you need to increase your pool stabilizer level quickly.

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Other Alternatives

Dichlor isn’t the only choice in chlorine for pool owners. There are several other options out there that may serve your needs better than dichlor. Here are a few of them.


Trichlor tablets cost less than dichlor and contain less cyanuric acid, meaning that the chlorine should work more efficiently. Adding trichlor can be automated by using an automatic chlorinator or a floating dispenser, making life easier and getting you in the pool faster.

If you use trichlor chlorine, be sure to check your cyanuric acid levels, so they stay in the optimum range.

Cal Hypo

Calcium hypochlorite, or Cal Hypo, is granular like dichlor, but it’s unstabilized, meaning it does not contain cyanuric acid or stabilizer. This makes it an excellent option for shocking a pool. Be careful, though – Cal Hypo can produce severe reactions to foreign substances, producing fires as well as fumes.

Sodium Hypochlorite

Liquid chlorine, or sodium hypochlorite, is not stabilized, so cyanuric acid would need to be added separately.

Salt Systems

An alternative to chlorine tablets is using a saltwater chlorine generator. With this system, chlorine is generated from salt added to the water. With these systems, there is less chlorine odor and softer water.

How to Get Crystal-Clear Pool Water

Apologies if this all sounds like a replay of your high school chemistry class. Sanitizing your swimming pool water shouldn’t be complicated. After all, you have a pool to enjoy swimming in crystal-clear, clean water, not to fret over chemicals.

Dichlor is a common type of granulated chlorine, but it’s not the best choice for every pool or every pool owner. Dichlor can be volatile and carries with it a risk of a stabilizer buildup, so care should be taken in storage and monitoring pool water’s stabilizer level.

Dichlor is more work for you as a pool owner since monitoring stabilizer levels, and manual application are both musts with this choice. It’s also nearly twice the cost of trichlor, an option that can be added with a floating dispenser or automatic chlorinator.

If you still want to go with dichlor to sanitize your swimming pool water, be sure to watch cyanuric acid levels and switch to chlorine without a stabilizer, such as liquid chlorine, if needed.

Questions? Let me know, always happy to help.

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