Hi Ben -

thank you for that information. Let me update you on my pool these last 36 hours since we spoke.

On Fri 6/10 at 8am the TC by OTO was >5 as indicated by a brighter yellow than the color on the top most cell. It did not turn orange or brown despite sitting for a while. Out of curiosity(and despite your advice) I tested with my FAS-DPD kit and got a FC of 9 and CC 22.5 ( is the OTO not picking up the weird chloramine that is being created by the baquagoop?)

at 2pm the TC by OTO was again >5 (fc 7.5 and CC 12.5) I added no bleach.

This morning sat 6/11 at 8am the total chlorine by OTO was still >5 but slightly less bright yellow than yesterday I think. (FC 5.5 and CC 5.5)

I have added no bleach since thursday the 9th.

I tested my hypothesis that I had a defective kit/reagents by doing the FAS-DPD on a sample of bleach water that I made up in the kitchen and of course I got a perfectly fine FC reading and a nonexistent CC - so there goes that hypothesis!

A lot of what you are saying makes sense as I review the numbers over the last few days - every time I have added bleach the FC rises a small amount but the CC rises a huge amount - supporting the theory that some weird chemical reaction is occurring to convert the fresh bleach not into free chlorine but some noxious chloramine substance. And it is slow to breakdown as evidence by how slowly my numbers are dropping despite no bleach added in 2 days.

what's weird is that the total chlorine level does not reflect the FAS-DPD total numbers - is it that the OTO can't pick up this new chloramine? Maybe it doesn't matter for swimming????

As you can imagine, none of the options you present seem particularly appealing ( not your fault . Do you know that the sodium percarbonate or copper sulfate will actually work or is that just a guess? I need to mull it all over and talk about it with my husband before deciding our next step.

But let me present this question to you - what is the problem with letting both the CC and FC drop to low levels like around 1-3 - and swimming in the pool over the summer. If I can maintain the FC at an appropriate sanitizing level, and keep the CC low enough so it is not totally offensive, can we just use it while the process of eating up the baquacil just continues over the summer? The pool is crystal clear and blue and so inviting!

My husband asks why, if we can swim in lakes and ponds that have such offensive materials in them, not swim in this pool? Any takers for that one???

I will continue to monitor the pool per your advice and not add bleach now. And then if we decide on the 2 new chemicals you suggested I will post with advice on doses.

Thank you again for all your help. aciam