Balancing chem after sequasol

[smokeygrl]

Hi everyone! I have been new this summer to BBB and it has been wonderful - crystal clear water all season!!! After I began the system I realized that some brown staining that I had at the bottom of the pool was metal stains and sure enough - my fill water had iron in it. I decided I would take care of those stains when I close this year. Anyway, last week, I needed to add fill water. I dropped the pH to 7.2. Added sequasol to the pool first, more than required on the bottle(per past posts I read by MBar) and put the hose in the skimmer to fill.
My problem seems to be that for the first time all season, I have some combined chlorine and need to shock. I'm a little concerned that I will end up dropping more metal stains onto my plaster. (21,000 gallon gunnite) If I bump my chlorine to 15.
#'s TC 9, FC 8.5, CH 250, TA 100, CYA 50
Any suggestions on how I should proceed in order to prevent this???
Can I add the chlorine to the skimmer and have the same effect as the technique of adding the fill water at the skimmer?
Thanks, in advance, to all.

[mbar]

I would take the chlorine up slowly - use regular bleach, bring the chlorine up 1 to 2 ppms at a time. You may not have to go all the way to shock, because you may be getting a cc reading from the sequasol. You can also put a trichlor puck in the skimmer basket if you have a sand or DE filter. DO NOT do it if you have a cartridge filter. Make sure your ph is not higher than 7.2. I would check the chlorine again too, a cc of .5 is not much and it may have been from the sequasol, and may be gone already. Let us know how it goes.

[smokeygrl]

mbar,
Why would the sequasol cause me to have combined chlorine?

[smokeygrl]

Marie, I just tested my water (7:00pm)....I know I shouldn't be - but I am shocked.....You called it: TC 5.5, FC 5.5 - no combined chlorine!!!
Still, could you tell me what the relationship is between the sequasol and chlorine? Thank you.

[mbar]

I think the sequasol shows up as combined chlorine when there is extra in the water and it doesn't have any metals to bind with. I am really not sure, but the water sometimes gets cloudy after a big dose of it, and that is what I think is happening. The clorine eventually gets rid of it.