Bromine or Chlorine for pools and spas

Many people have a lot of questions when it comes to chloride and bromine and which to use in their pools or spas. This has been debated for the last twenty years at least. Which are better? Which are safer? Which is cheaper? This article is to explain the differences, benefits, and downsides of both of these commonly used chemicals. Chlorine comes in three main forms for pools and spas:


Granular Concentrate

Tablet or stick

Bromine is available in fewer forms but is very efficient when used under the right conditions…

Chlorine: The Old Workhorse

Chlorine comes in many forms. The three main forms you see for pool sanitation is liquid, tablet, and concentrate. When you add chlorine to your pool you are seeking to add what they call free chlorine. Free chlorine is the chlorine that is still available to actually sanitize your pool.  It kills bacteria and oxidizes (fancy way to say get rid of) contaminants, such as ammonia, soap and other nitrogen-containing organic compounds. When these free chlorine combines with these contaminants it makes what they call combined chlorine. Look at combined chlorine like a spent bullet; it has done its job now you must get rid of it. When your combined chlorine is above .2 PPM (that’s parts per million folks) you should shock it. Shocking it is superchlorinating it. Superchlorinating will get rid of the combined chlorine and get rid of all the nasty stuff it has bound itself to for good. To figure out you combined chlorine you can do a simple equation of total chlorine minus the free chlorine you have and it will tell you how much combined chlorine is left in your pool or hot tub.

But back to the subject matters at hand though, the three types of chlorine.

Liquid: Tried and True

The foremost and most commonly used is liquid chlorine. This is the most commonly used chlorine because it’s what people are familiar with. Most likely if you grew up with a pool you used plastic jugs of liquid chlorine, but you like me might have bad memories of using this type of chlorine. You might remember the awful experience of having it splash on your cloths and like bleach leaving white marks on your clothes forever after that.  Liquid chlorine loses its potency quickly so if you don’t get it fresh it will be less effective.  Look for stores that are turning a lot chlorine as source for fresh liquid chlorine.  Have no fear though, liquid is not the only choice now. The two other choices are concentrate and tablets.

Concentrate: Powerhouse of Cleaning

Concentrate also commonly called granular is a white crystal-like powder that can be broadcasted (thrown) across the surface of your pool to dissolve in the water. Concentrate is known also by its industry name of Di-chlor, because it’s made from Sodium Dichloro-s-triazinetrione. But don’t worry you don’t have to know that just go into any pool supply store and ask for concentrate or granular and they will know what you are talking about.

Tablet: Easy and Effective

Another easy to use system is the tablet form. The tablet forms are just concentrate chlorine packed into a round form that you can put in what the industry calls a floater. A floater, which are often designed like a duck or a turtle, are a floating device that two or three tablets can be put into to dissolve slowly over time in the pool and give you a constant stream of chlorine in your pool. Tablet form chlorine is also known by its industry name of Tri-chlor because it’s made with Trichloro-s-triazinetrione. Again don’t worry no pool service person will quiz you on this and if you say tablet they will know what you are talking about.

Why Chlorine?

Now why should you pick chlorine? Well there are a lot of reasons chlorine might be right for you. Chlorine has been proven to be effective for years and is easy to find and now with the three different kinds is relatively easy to use depending on what works for you. Also chlorine unlike its sister bromine has stabilizer in it. Stabilizer is an added chemical that will stop UV rays from breaking down the chlorine before it does its job. Why do you need this? If you have a pool UV rays are hitting all that surface area. Without stabilizer added to your chlorine you would have to add stabilizer after the fact to make sure the sun doesn’t burn up all that chlorine working to clean your pool. Now what about the environmental effects of chlorine you might ask? Pools have a very small impact. Chlorine and bromine are used in fair more quantities for electronics and computers. Also you pool is a closed system that isn’t even entering the groundwater. The water out of your tap probably has more chlorine and more unbalanced pH then your pool water and that’s fine to water the grass with right?


You might be asking yourself why I should use bromine over chlorine for my pool or spa. Bromine does have some uses that it is perfect for. Bromine is ideal for hot tubs and spas because it works better at higher temperatures and smaller volumes then chlorine.

Bromine is not stabilized though like chlorine and therefore is harder to keep in good levels in larger pools that receive a lot of direct sunlight. Bromine like chlorine has two types free and combined. But unlike chlorine in bromine both the free and combined work as sanitizers.

So when you test bromine unlike chlorine you should test the total bromine because all the parts work as effective cleaners. To have the combined bromine work all you have to do is add shock and this will reactivate the bromine. There is a lot of chemistry I could throw at you why this works this way but who really needs to know that when you know it works.

This does lead to a small problem though. Bromine is so stable it is difficult to get out of the water. Ideally you only need to add bromine once and once you have a bank of bromine in you can just add non-chlorine shock to keep it working. Also if you are using bromine in your hot tub and have a pool attached to it you should use bromine in the pool too. This is because bromine will turn the chlorine you add into bromine. So if you use bromine in one you should use it both your pool and spa especially if they are attached.

There are some problems with bromine though. There are reports of some types of algae and fungi that have not been killed with bromine. And some people with sensitive skin have complained that bromine irritates their skin more then chlorine. So as a rule of thumb though if you have a big pool without a spa and lots of sunlight pick chlorine but if you have a spa you should probably go with bromine.

Related Posts Plugin for WordPress, Blogger...


  1. You will need all those accessories and definitely more than just chlorine for water maintenance. What chemicals you need depends on your source water. I recommend getting your source water tested before you buy any chemicals. If you have a pool store close by they should test your water for free and let you know what you need to balance it. Usually you will need to balance your alkalinity, pH and then sanitizer and shock your pool. The process sound more difficult than it is. Once you have your pool up and water balanced maintaining it will become second nature.

  2. Super great post! Honestly..

  3. You have done it again. Incredible post!


  1. […] Bromine or Chlorine for pools and spas | Pools Billiards and More […]

Speak Your Mind