UPDATE:
Pool guy succeeded that he didn't know what was going on with it, and he didn't have time to figure it out and mess with it.
Great! [insert sarcasm.]
A few days and phone calls later I had someone to take care of it. It took EIGHT man hours to brush it all out. All billed hourly. $250.
But the good news is that it hasn't showed back up!
I don't know specifically what chems were added, but I'm told the conclusion was it was either dark green or black algae.
Along the lines of more good news, the old pool guy feels his $550+ invoices should still be paid.
Um, no.
Because he's a small business I offered to pay $150 (figuring cost of standard chems at $25 per week). He's not satisfied with that. I'm trying hard to politely tell him that had he been competent (in time and knowledge) in taking care of the pool from day 1, it never would have gotten this out of hand.
Dude, don't go away mad. Just go away!