Update: I ran out of daylight vacuuming to waste, so did not shock. I did add both gallons of HCL, and as of this morning I only noticed a slight improvement in the CYA. I did notice that it appeared to bring down both TC and FC readings. I plan to finish vacuuming visible algae after work. I think I should add another gallon of HCL (?) before adding the the liquid chlorine.

Test kit has been ordered and appears to be on schedule for a 8/7/14 delivery. Sorry I don't have better info at this time.

I failed to mention that the pool utilizes a sand filter (not sure what brand, but it's black with a multi-function selector on top), a 2-hp Hayward Super Pump. I replaced the sand 4 or 5 years ago. Solar blanket provides more than enough warmth. Unfortunately, this pool gets sunshine almost the entire day. I am currently removing the blanket at night to let some heat out. Current temp and humidity isn't helping much.