Chlorine vs Free Chlorine

Jul 22, 2018
38
Babylon
What's the relationship between Chlorine and Free Chlorine? Are they one in the same. My Chlorine level is about a .5 right now. I want to raise it to about 3 or 4 ppm. I want my FC between 5 and 8. Is there a method to balancing Cl and FC independent of one another?
 
Three kinds of chlorine: Free, Combined, and Total. Free is FC, which is available right now to kill anything. CC is combined, sort of half-way used up. Total is the sum of both.

So FC + CC = TC. In a perfect world, CC will be zero, so FC = TC. Your TF100 kit does the FAS-DPD test, so it will tell you precisely what each component is.
 
Roger,

You also don't just decide where you want your FC... Your FC is dictated by the level of your CYA (Stabilizer) and is outlined in this chart... [FC/CYA][/FC/CYA] Notice that there are two charts, one of normal pools and one for saltwater pools..

Thanks,

Jim R.
 
Three kinds of chlorine: Free, Combined, and Total. Free is FC, which is available right now to kill anything. CC is combined, sort of half-way used up. Total is the sum of both.

So FC + CC = TC. In a perfect world, CC will be zero, so FC = TC. Your TF100 kit does the FAS-DPD test, so it will tell you precisely what each component is.

Thanks.

So hypothetically speaking the oto chlorine test and the 0870 chlorine test should give me the same results?

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Roger,

You also don't just decide where you want your FC... Your FC is dictated by the level of your CYA (Stabilizer) and is outlined in this chart... [FC/CYA][/FC/CYA] Notice that there are two charts, one of normal pools and one for saltwater pools..

Thanks,

Jim R.

Yes I am following the chart.
 
Thanks.

So hypothetically speaking the oto chlorine test and the 0870 chlorine test should give me the same results?
Yes, theoretically.

The problem is that the shades of yellow are hard to differentiate. To me, anything between 4 and 7 looks like 5 on the OTO colorblock. And that's after a couple years of doing both tests to see if I can get good at colormatching! Just the other day I tested with OTO since I was testing pH anyway. It looked like 3 to me. The FAS-DPD test said it was 1.5 FC, 0 CC.So I looked at the colors again, and sure enough, it was closer to 2 than 3.
 
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