I test my chlorine almost daily, but never seen it this dark before. It's like dark yellow, gold or even light brown. My chlorine level is about 6.5 (using 870, 871), CC 0, CYA 45, PH 7.5, TA 80.

I used 8lb baking soda to raise TA to 80-85 last week. Also, the water temperature is probably below 70 now.

I was using 2 types of tablets in two floaters (leslie's and aquachem) for the last couple of weeks and now waiting for the chlorine to drop so I can close the pool.

Is this color normal? what's causing it?

thanks.

The OTO test (yellow chlorine) only reads up to 5ppm on the color block. Any darker, means it's over 5ppm, totally normal. Which you verify that it is with the FAS-DPD readings.

Why are you using both at the same time? One or the other is good enough.

I don't use both all the time, I just didn't expect my chlorine to hold this high for so long. By the way, I find FAS-DPD easier to use and I think it's more accurate. I think I see over 5ppm on OTO while it'll be 3.5ppm on FAS-DPD. I wish there were agents for PH test, because what I see as 7.5 stores that use lamotte waterlink as well as leslie's see as 7.8.

I just never seen chlorine this dark before. It is as dark as baking soda box. The OTO test kit is from last year and may be that's the reason.