Janet,
Thanks for the reply.

I have been testing with strips, but based on your comment I'll pick up a drop-based kit today and run that. Last year I used the Frog chlorine bac pac plus occasional use of shock (1lb bags of 68% calcium hypochlorite). I don't have the CYA number from end of last season, but it was significantly higher. I did drain about 1/2 the water down and re-filled it (well water). And I used an algaecide and clarifier as part of the pool opening.