It’s a scenario that most swimming pool owners encounter at least once. You’re pouring in the usual amount of chlorine when you realize that you don’t have as much as you need. Is it okay to mix the chlorine in your pool with another type? Can you switch chlorine types all together?
You should not mix chlorine types if you already have chlorine in your swimming pool. When the different types of chlorine combine, explosions or combustion could occur. You shouldn’t even store different types of chlorine in the same part of your shed.
If the above information was eye-opening for you, we have lots more to talk about in this article. We’ll discuss further why mixing chlorine is such a poor idea and if you can switch between different types of chlorine. Make sure you keep reading!
Can You Mix Different Types or Brands of Chlorine? What Happens If You Mix Chlorine Types?
Not all chlorine is created equal. Here is a quick overview of the different types.
- Lithium hypochlorite: Lithium-Hypo chlorine is a granular product that contains up to 35 percent chlorine. Although it cleans swimming pools well, Lithium-Hypo is more expensive than most other types of chlorine, so it’s not something that you see everyday pool owners use all that much.
- Chlorine tablets: It’s so convenient to toss a few tabs of chlorine into your pool and let the stuff do all the hard work. These tabs are commonly known as Trichlor.
- Sodium dichloroisocyanurate: The chlorine product called Dichlor is a powder sanitizer that contains up to 65 percent chlorine. It can double as pool shock, so it’s a common product that pool owners use.
- Calcium hypochlorite: Cal-Hypo is another type of powder chlorine that’s even more powerful than Dichlor. It can contain upwards of 73 percent chlorine thanks to the presence of calcium carbonate and calcium chloride.
- Sodium hypochlorite: Just think of sodium hypochlorite as liquid bleach. As a strong disinfecting agent, you can pour it in using large quantities and your pool will be cleaner. More commercial pool owners and managers use sodium hypochlorite than homeowners do.
Whether you prefer liquid chlorine, powdered chlorine, or chlorine tablets, you should never mix the types or brands of chlorine you’re using.
If you’re in a situation like in the intro where you run out of chlorine midway through cleaning your pool, then stop what you’re doing and go to the store to buy more. You can even send a family member or neighbor out while you continue cleaning your pool.
Why not just uncap a different type of chlorine and pour that in to make up for the difference? What happens if you combine chlorine?
Although chlorine is itself not flammable, when it’s near other types of chlorine that may contain different chemicals and compounds, then it can become flammable.
If the chlorine goes up in flames, it can lead to explosions in your backyard. Should you and your family be nearby, you could be seriously injured or even killed.
Related Reading: Can You Add Pool Chemicals All At Once? (answered!)
Can You Switch Chlorine Types?
Now that you’re aware of the risks of combining different types of chlorine, you plan on treading a lot more carefully in the future.
At any point, are you allowed to go from liquid to powder or granular chlorine or should you only stick with one type?
You can switch the type of chlorine you’re using, provided you’re not adding the chlorine at the same time. In other words, if you usually use liquid chlorine and the last time you chlorinated was several days or a week ago, you can now use a powder or tablet chlorine product to clean your pool.
By this point, the liquid chlorine in the pool should be long gone or on its way out of the water. It wouldn’t be strong enough to trigger any sort of adverse reaction.
Can You Mix Dichlor and Trichlor? What about Trichlor and Calcium Hypochlorite?
To recap what we talked about in the first section, Dichlor is a type of powdered chlorine that contains up to 65 percent chlorine. Trichlor is your common chlorine pool tablet. Is it okay to combine them together?
No, it isn’t. Dichlor is rather sensitive to other chemicals. Remaining residue from other chemicals, including different chlorine and acid, will likely cause an adverse reaction, which may result in explosions depending on the conditions the chlorine is being stored or used in.
Here’s another reason not to mix Dichlor and Trichlor if you’re not totally convinced. You’re spending a lot of money that way, as Dichlor costs at least two times what you’d pay for chlorine tablets.
If you’re not sure whether to use Trichlor or Dichlor, we’ve got you covered:
Should You Use Dichlor or Trichlor for Your Pool?
Speaking of Trichlor, is it ever okay to mix it with calcium hypochlorite or Cal-Hypo?
Again, the answer is no. Cal-Hypo is an alkaline product, which means that on the pH scale, it’s more basic. Its pH would be higher, between 8.0 and 14.0. Trichlor is more acidic, in that it’d fall in the pH range of 1.0 to 6.0.
By combining the two products in pool water, they will dissolve and lead to a chemical reaction.
The reaction created by mixing Cal-Hypo and Trichlor produces chlorine gas. The fumes are toxic and could even be deadly. Since you’re outdoors, it’d be unlikely for you to breathe in a high enough concentration of chlorine gas to kill you, but don’t be fooled. The stuff is fatal.
Oh, and the heat produced by the reacting chlorine chemicals could potentially cause a fire or explosion too. Don’t do it!
Can You Mix Liquid Chlorine and Chlorine Tablets?
Powdered chlorine doesn’t mix well with Trichlor aka chlorine tablets, but what about liquid chlorine?
We’re sure you already know what we’re about to say here. No, you should not combine these two types of chlorine.
As has been the case throughout much of this article, the chemical combination of mixing liquid chlorine and chlorine tablets can produce heat that can start a fire (or an explosion) while simultaneously releasing toxic fumes.
Can You Mix Different Pool Shocks?
Let’s say your pool is incredibly filthy, so you decide to shock it back to a state of health. Perhaps you were already using a shock like Dichlor, and you want to add a second type of shock to the pool as well. Is this necessary or safe to do?
It’s not necessary and could do your swimming pool more harm than good.
When you use stabilized chlorine like Dichlor and combine it with another form of stabilized chlorine such as a different type of pool shock, the stabilizer can oversaturate in the water.
The chlorine kind of cancels itself out after that. It’s not helping your pool be cleaner and adding more chlorine won’t do much of anything either. Your best plan of attack at that point would be to remove all the water in your swimming pool and refill.
If your swimming pool is on the larger side, then you know what an absolute pain that would be. Our best advice? Use one form of pool shock at a time. Give it adequate time to work, and if it doesn’t, then you can explore other options.
Related Reading: Can I Add Muriatic Acid All at Once? | How to Safely Add
How to Safely Add Chlorine to Your Pool
Even working with only one type of chlorine has its risks. That’s why, in this section, we thought we’d explore how to add chlorine in your pool in a safe manner.
First, we recommend selecting one type of chlorine you’ll use. As we touched on earlier, even storing different types of chlorine in the same storage shed can be a recipe for disaster. In certain conditions, the chlorines could potentially explode or release fumes.
Here’s how to apply chlorine depending on the type you selected.
Adding Liquid Chlorine to a Pool
- Commercial-strength liquid chlorine (aka bleach or sodium hypochlorite)
- Rapidly eliminates algae, bacteria, and other contaminants, ensuring crystal-clear water
- Safe for pools & spas (saltwater & chlorine systems)
- Use as a shock or regular sanitizer
Although the jugs are heavy and hard to carry (for most of us, anyway), liquid chlorine is a popular choice for many swimming pool owners due to how easy it is to use.
Depending on the brand you select, you only have to measure out the amount you need, pour the chlorine into the cup, and then dump the chlorine in your pool.
We recommend always wearing protective gear when handling liquid chlorine such as gloves and even goggles (you never know if the stuff could splash). Although it’s hot out, wearing long sleeves and pants is safe to protect your skin from those same errant splashes.
Oh, and please wear clothing and footwear that you don’t care about when chlorinating your pool. Liquid chlorine is bleach-based and will stain your clothes and shoes!
Adding Tablet Chlorine to a Pool
- 3" chlorinating trichlor tablets
- Contains stabilizer to protect against sunlight
- Prevents algae and kills harmful bacteria
You’ll recall that chlorine tablets are popular among pool owners since they’re so low-effort. You buy the bricks or tabs, insert them in the special feeder system, and then put the feeder system in your pool.
Over time, the tablets will dissolve, releasing chlorine into the pool gradually. When the chlorine tabs are gone, it’s time to refill the feeder system.
Adding Granular Chlorine to a Pool
- Dichlor chlorine with stabilizer to resist UV light
- Dissolves quickly & kills algae & bacteria
- Safe for pools & spas (salt & regular chlorine pools)
For those with a bigger budget who want to use granular chlorine such as Lithium-Hypo, chlorinating your pool is a more complex process. Let’s explain.
First, you need to test for free chlorine in the pool water to determine your Lithium-Hypo dosage. You’ll also need a bucket and a measuring cup.
Fill the bucket with pool water three-fourths of the way full. Then add the recommended amount of granular chlorine. Using a paint-stirring stick, begin stirring the ingredients. All the chlorine should be dissolved.
Next, pour the bucket into your pool incrementally.
Mixing different types of chlorine is never a good idea. The chemical reaction that occurs could lead to fires, explosions, and noxious fumes that are not safe to breathe in for prolonged periods. Do yourself a favor and stock up on one type of chlorine at a time!