After considering my post I realized that no one can really help with the chemistry without numbers so I dug out my PS233 and tested.

As I figured I have

FC - 0
CC - 0
TC - 0
pH - 7.2
Alk - 80
CAL - 120
Cya - 0

I'm still baffled about why the overgrowth of algae. I bumped up the CL levels and added a quart of Polyquat before closing the pool down thinking that I'd have a clearer opening this year than last. My numbers were solid at that time and the water sparkling clean.

I'll be heading off to get some Clorox tomorrow.

Thanks for any other suggestions, especially about the filter clogging up with sludge or not.

CoffeeBean