After playing the pool store game for three years I'm ready to understand my pool's chemistry and take over its maintenance.
I have had to shock my pool with calcium hypo every other week, while using about 6x 3-inch tablets per week, just to keep any chlorine in it and I don't think that is right - since it did not keep algae from growing last year. Your explanation on the effects of trichlor and calcium hypo in the water's chemistry now make sense. I was even sold on buying and using Kleen Pool Algeacide this year, which may have been my biggest mistake.
I have ordered a TF-100 test kit and I'm ready to start using liquid bleach or chlorine and follow this forum's advice. I'll be posting more questions once I get my kit and start testing.