Slamming bromine/chlorine pool

[Calais Marie]

Hello

I stopped using bromine tabs in my pool several months ago and simply switched to using chlorine, as I've read that it will simply and cheaply re-activate the bromine bank. I might only drain and refill next year.
I received my tf100 kit in July and have been testing diligently. I started chlorinating with Trichlor pucks and then switched to cal hypo 73% once the CYA reached 30. I've been maintaining FC around 7 (perhaps that's FB at 14?) and my CC has always been testing at 1 (CB at 2?).

I recently had a problem with foam on the surface, and so considering the CC level as well, I decided to do a slam. Btw, the water has been crystal clear since I started using the tf100 in July.
The OCLT has never gone above 1 since I started the slam process four days ago and really I'm only losing 0.5 - 1ppm FC over 24 hrs. (Indoor pool, very little direct sun, zero bather use, and clear water before starting).
I've brought the CH up to 325 and the foam is going away finally but the CC is taking 2 drops of r0871 to clear the test samples.

My concern is that the FC (FB?) is holding on its own pretty much at a slam level, but this is not affecting CC (CB?).
Because there is bromine in the pool, should I be looking for different results, reading the results differently or be doing different tests altogether? I would like to use the pool but am a little concerned about the CC level. Should I be?

Here are some of the test results:

Before slam:

Fc 7
Cc 1
Ph 7.3
Cya 30
TA 80
CH 200
Temp 72 Fahrenheit

First night into slam:
Fc 12.5
Cc 1

First morning
Fc 12.5
Cc 1

Second night
Fc 11.5
Cc 1
Added 1.5 litres of 10% bleach
Added ~ 4-5 litres of calcium chloride

Second morning
Fc 12.5
Cc 0.5 - 1.0 (not certain)
CH 325

Third night
Fc 12.5
Cc 1
CH 325

Water continues to be crystal clear and I've brushed and vacuumed a couple of times. Sand filter pressure has not risen enough to warrant a backwash yet.

Thanks for your help!

 

[JVTrain]

Indoor pools can be problematic for CC as they don't get much UV sunlight. UV light helps break down CC species in the water and without it, some can be persistent. If you want to try to reduce the CC, you can try using some monopersulfate shock (MPS). MPS is better at breaking down CCs than hypochlorite and can be useful for indoor pools and spas. It's more expensive that using bleach for sure, but in your case with indoor and low/no UV light to help you out, it is worth a try. Usually dosage rates for MPS are 1 pound per 10K gallons.

The caveat with using MPS is that MPS itself will show up as CC on your testing for about 24 hours or so. There is a reagent to eliminate MPS interference with the FAS/DPD test but it's fairly expensive. If you do dose with MPS, ignore your CC reading for 24-48 hours after dosing. After that, your CC reading should be accurate again to see if the MPS helped.

CC of 1 is right on the borderline and is a concern but if you need/want to take a swim or two, you should be fine... as long as your FC level is below shock level (<12) during the swim.

 

[Calais Marie]

Thank you for the advice. I'll be treating the pool today and let you know how it goes.