Thanks Watermom!
Our pool holds 8000 gals. We have always exclusively used a product called Shock PLUS (by aqua chem). They are 1 pound packets that treat 12,000 gals. I don't know why we started using an entire packet per treatment, but we did. Like I said before, our problems started three months ago with our new pool. The active ingredient is sodium dichloro-s-triazinetrione (58.2 %). The remaining 41.8% is "other ingredients". The package instructs to use once a week to create sparkling water, reduce chlorine odor and eye irritation, and does not increase pH.

I can work on the pool in the morning and evening, but for the rest of the day, this being Texas, the sun is unmerciful. Could it be the sun? We lost a shade tree and one of our pool umbrellas so we have many more hours of direct sun on the pool this year. In any event, I will start the bleach regime and let you know.
Judi