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Water chemistry for the pool guy. Pool Chlorine

When you start out in the pool industry the first thing that you need to learn is proper pool water chemistry. Most people think it’s just about chlorine and Ph, but there is a lot more to it than meets the eye.

Chlorine – You will need to learn about the 3 types of chlorine and why you don’t want combined chlorine.

Here are the 3 types of chlorine:

Free Chlorine -This is the one that most pool guys will test for and is the chlorine that is available to sanitize. The reason you are adding chlorine is to disinfect or kill harmful microorganisms and keep the bathers safe from those harmful microorganisms. This is the one that is doing the hard work for you sanitizing the pool.

Combined Chlorine –  Once the free chlorine in the pool is mixed with ammonia and nitrogen it will form combined chlorine and its ability to disinfect his hindered. Not every pool guy will check for combined chlorine. Don’t be one of them. You need to make sure your test kit has the ability to test for both free chlorine and total chlorine.  Why is it so important to test for combined chlorine? It takes 25 parts of combined chlorine to do the work of 1 part of free chlorine. What does that mean for me the pool guy? It will take a lot more chlorine to achieve your goal of keeping the pool clean, disinfected and safe for the swimmer. It will also, translate to higher chemical consumption and cost for you. How do I know what my combined chlorine is? Test your free chlorine and then test your total chlorine. If your total chlorine is higher than your free then the difference is combined chlorine.If your free chlorine is the same as your total chlorine then no combined chlorine is present.

You always want your free chlorine (FC) and total chlorine (TC) to be the same.  If they are not then using this formula will help you figure out your combined chlorine. Subtract your TC from the FC.

TC – FC = CC. Example – Let’s say that your Total Chlorine (TC) is 5ppm and your Free Chlorine (FC) is 3ppm then subtract 5 – 3 = 2. 2 ppm is your Combined Chlorine (CC).

When looking at the AquaCheck Pro test strip you can see the Total Chlorine and the Free Chlorine one right underneath the other and is a quick way to test it. Just make sure that they are both the same. If they are the same then you don’t have combined chlorine. You can also use test kits such as Taylor test kits to check for both free chlorine and total chlorine.

Total Chlorine – Total chlorine is the combination of Free Chlorine and Combined Chlorine. FC + CC = TC.  Some Taylor test kits and some test strips such as the AquaChek Pro will allow you to test for total chlorine.

Click here for Swimming Pool Water Chemistry For The Pool Guy (PART 2) – pH

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