Adjust CYA during shock process?

May 23, 2013
49
Rockwood, Michigan
Hi.
I've successfully used TSP method on my pool the last 2 years - going from green (thanks to Loop-Loc cover) to clear and eliminated all problems during season with lower chlorine usage and filter run time.
I am helping a wife's friend (divorcee with no help) get her pool started this year - had a cover blow off and never reinstalled so big time green. Above ground 7,500 gallon pool (much smaller than mine).
Started the shock process last Thursday - so going on 5 full days. Cleared green in 3 days...working on extreme cloudy condition now.
When I started, CYA registered below 20 (can't measure with TFT100 kit then) but didn't concern myself with it.
Pool is mowing through chlorine still - 2ppm loss per hour in sunlight. While clearing cloudiness, I'm sure some loss because of CYA deficient.
Should I go ahead and adjust CYA...or wait until we get clear water?
I have been targeting 10ppm for shock process. CC started at 1.5, and is now 0.5.
I'm leaving Friday at which time she'll be on her own for a week....would like to do the best thing I can to have her at / near success if any suggestions.

Thanks.
 
Is the water clear enough to be able to test the CYA? Having a lower CYA level means you need less CL to clear the algae with the SLAM method, but you need a base amount of it to prevent loss to the sun too. I'd get the CYA to a level of 30 or so and then proceed to SLAM. You can adjust it higher if you want to later.
 
Water is still at an extreme cloudy condition, but no green. Still keeping at shock level day 5.
Yes I thought about the less CL to clear water, that is why did not immediately adjust but if I can save some $$ on chlorine by improving the loss per hour because of sun thought I'd do that.
Is it OK to add solid CYA while pool is in the midst of shock process?
Since I can't measure, thought I'd add to raise 10ppm.
She has new bottle of CYA that is add to skimmer type.
 
Yeah that's fine though we recommend putting it in a sock in front of a return. If you put it in the skimmer don't turn off the pump. But don't do this if you're still having to stop and clean out the filter as part of the SLAM process. The powdered stuff doesn't dissolve right away and will embed itself in the filter until it does. If you have to stop and clean the filter you'll essentially throw the CYA away. If you do add CYA make all of your CL adjustments as if the full amount of CYA has already dissolved, etc.
 
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