Ok, thanks for that. It may just be the differences in available light.

Next question: I've read in another thread here that bleach and LC deteriorate over time. Does high heat tend to accelerate this? I don't have a temperature controlled environment to keep my bleach in (no A/C in the house), so I keep it by the pool in a shaded area.

I suspect that currently I am "teasing" the algae, as I am still having a very small amount of regrowth overnight, and still losing 5 -15ppm overnight (dang it all, NEED those CC readings!!). Assumption is that the 100+ weather is destroying the bleach before I can get it into the pool. By late afternoon even with dosing the pool multiple times during the day, the water goes from having the chloramine smell back to swamp water odor by sundown. Not sure what is happening here.

Using the dilution method until my kit arrives on friday, I'm trying to keep the chl at 20 - 25ppm, but I fear that the loss of effectiveness of the bleach is slowing the clean-up process considerably. Also, the water is beginning to take on a slight "salty" taste.

Correction: just came in from the pool, and the overnight regrowth HAS diminished greatly over the original appearance several days ago. Only a small amount in the wrinkles of the floor, compared to every wrinkle having been filed with the algae dust. But then, I dosed VERY heavy last night at sundown, FC level unknown. This mornings reading is between 15 - 18ppm.