adjust cya before or after shocking

[aylad]

Once you get the algae killed off, you're going to need to raise your CYA levels to help protect your chlorine from the sun. When that happens, you're going to have to raise your chlorine levels to compensate for that. Look through this thread for some of the sigs that have the link for the "best guess chlorine chart", and that should answer your questions regarding higher chlorine levels.

In looking at your chlorine log, you simply did not sustain the chlorine levels long enough to kill the algae. As we've said many times throughout this thread, you need to get it to the 15 ppm make and keep it there until the algae is dead. By letting the chlorine levels yo-yo up and down like that, you may be preventing further algae growth, but you're not doing anything to kill the original bloom.

I don't really rely on CC readings for algae determination....sunlight and chlorine both help eliminate CC. I have personally seen algae on the side of my pool with a CC of zero. That's why a much more reliable test is to see no chlorine consumption overnight.

[Kateyru]

I was actually in the process of raising CYA level when the algae made itself known (to me) so I'm clear with that.
I do think I understand most of this now. In my previous shock attack, somehow the focus and comments back and forth got on FC loss from evening till morning coupled with minimal CC. The length of time my FC was at or above 15 ppm seems to have gotten overlooked it.
Many thanks again!