Please Help / Advise

[DavidD]

First, I think your CC level of 6 is suspect. I would definitely test it again.
Secondly, you should get your FC level higher than 2.5, say around 10 ppm, and hold it there for a couple of days (CC is the "poop" you mentioned previously, or also known as used up FC. Shocking will inturn get rid of it.). This will require shocking and I'd use plain ultra bleach. I'm not sure how many gallons it will take since you didn't say how many gallons your pool is. You will have to add it several times a day, brushing and vacuuming to waste at least once a day. You could also use Cal Hypo to shock but since you didn't post CH (calcium hardness) numbers it is not at the top of my recommendations since your CH level may be high from last years shocking.

Since your CYA is 0, I see nothing wrong with using the "pucks" after you get rid of the algae but keep a close eye on PH as they tend to lower it rather quickly. Don't use them now and empty your feader if you have one while using the bleach. You should also post your ALK numbers as well. Hold off putting any other chemicals/clarifiers in the water until this problem is resolved.