Hi RCCI:

With THOSE numbers I doubt it's scale at all...more like some kind of algae! Scaling occurs when your CH and TA levels are too high, and that's not the case Let's look at those numbers again:
FC 2.0
tc 2.0
CYA 60
pH 8.0
CH 150
TA 110
tds 1000

I see CYA= 60 and FC=2 AND pH=8! Whoa! Our Best Guess table says that when CYA is between 60 and 90, you MUST maintain FC between 5 and 10ppm, and shock at 20 ppm. On top of that, chlorine is LESS effective when pH is too high, as yours is at 8. You would have NO problem growing algae in that!

Further, recommended levels of CH in hard-sided pool like yours is 200 to 400ppm, and you're BELOW that at 150 and TA is 110 (and, if pH was where it should be, TA would be even lower), well within recommended levels. I don't see how you can have scaling.

The only other possibility I see is a high iron or copper content, which the TDS score MAY indicate, but I have trouble believing that. Even so, 20 gallons of Muriatic Acid isn't the correct treatment.

I'm betting you have an algae bloom, plain and simple, and the test numbers agree with that. They do not agree with calcium scaling to the best of my knowledge.

Unless this PB is known for standing behind his pool, I would not consider adding 20 gallons of acid unless he instructed me to do so in writing...otherwise..."No yeronner. I never said put 20 gallons o' acid in. Nobody in his right mind would tell a pool owner that..." and it's your word against his.

Meanwhile, we have some commercial and metal content experts here and they can look at this thread and tell better if the PB is on target or flat-out nuts.

Carl.