Started my Baq conversion today. I put in 420 oz. of 6% bleach to get my FC to 15. 1 1/2 hour later my FAS/DPD test showed.....
1. after 10ml of pool water and one heaping scoop of powder sample didn't turn pink but possibly the slightest hint of pink
2. as I continued to add drops the sample became more and more pink with each drop

I was confused by this and stopped the test at about 30 drops.

3. Repeated the test and got identical results.
4. OTO test shows 0 chlorine.
I assume I have 0 chlorine but I don't understand why FAS/DPD test progressed towards pink as i added drops.

Thanks for any help!!!

I'm guessing that it's CC interference and the FC was very low/nil. Which drops were you adding?
If the yellow OTO shows 0 then it's zero

Good luck we're here to assist!

Added the R-871 drops. Sounds good!

Try adding some more bleach and testing within 30 minutes with the OTO. If you see Yellow, the test with the FAS-DPD test. If you add a scoop, and it doesn't turn pink, add another scoop.

Chlorine gets used up extremely quickly at the start of a baquacil conversion, so the zero FC level doesn't surprise me.

I spoke with Barbara_C on the phone about her test results. I completely agree that the FC could've been used within that time frame.

What puzzles me is, after the DPD Powder was added, each succesive drop of R-0871 produced a steady increase towards a rosy pink in the solution until she stopped at 30 drops.

I have never heard that reported nor am I aware of any interference that would cause that response.

OP is redoing FC addition and will test within 30 minutes of dosage with the FAS/DPD.

That's why I thought maybe she was using the wrong drops...

Perhaps adding to the confusion......

OP has reported that continuing into the CC's test, the solution turns a deep rosy pink immediately upon addition of 5 drops of R-0003. After 5 drops of R-0871, the solution turns completely clear.

0 FC CC 2.5?

I'm afraid I'm adding another variable to the equation.
The filter needed to be backwashed due to low pressure. I now need to add fresh tap water. That should help it would seem. We'll see.

Hang in there!

I didn't take chemistry in school so now I'm getting a crash course! It's all good.