We just got our readings. It says that the Free Chlorine and Total Chlorine is below the recommended values but the Combined Chlorine is above the recommended value.
Why is this? If I increase the Free Chlorine and Total Chlorine to the recommended values, won't this put the Combined Chlorine way above the recommended value?
Look forward to your reply.
Hi gain Judy. I know the FC, TC, and CC can be a bit confusing. I did make a video on it. A simple way to look at it is this. I'm going to go on ounces. You're on the easy metric system and we're still living in the 1800s. 😂
You have a bottle of glass cleaner that holds 16 oz. That's the total amount of cleaner (total chlorine) you have. You spray the window with, say 1/2 oz. That the amount that's going to clean the glass (free chlorine). You didn't use the full bottle to clean the glass, just enough to do the job.
Total chlorine is ALL the chlorine in the pool, regardless of if it's being used or not. You can have a clear pool with 5ppm chlorine, and then a leaf drops in the pool. Not all of the 5ppm is going to kill the leaf. Let's say only 0.5ppm went to go kill it. That 0.5ppm is now used up and no longer good, BUT, it
still registers as "chlorine". So now you have 4.5ppm chlorine that is ready to kill organic matter.
The difference between the TC (5ppm) and the FC (4.5) is 0.5ppm (CC).
Free chlorine is the amount that is actually being used right now to kill organic matter.
It's really not that necessary to concern yourself with the CC. I've found it's mainly for indoor pools that have that "chlorine smell" and need to be shocked on a regular basis due to being in an enclosed area without good air flow and ventilation.
I don't have your size pool but you may want to supechlorinate the water and being it up to 15ppm. First, drop the pH just a bit to 7.2 using muriatic acid, then add 1 gallon of liquid chlorine or bleach per 10k gallons. That's the baseline and is applicable regardless of where you are. You might need to convert the gallons of liters, or however you measure it.
Filter for 10 hours then retest the chlorine. If it decreased more than 2 - 3ppm add enough chlorine to increase it back up to 15ppm. Clean the filters. This will take care of the CC issue. Very simple to do.
Thanks for the video and information. I now understand it much better and hopefully I will be able to maintain the pool better now.