OK, so I visited my Pool company and they checked my CYA for me....they say it's 100.
I have a call in to the county about the metal levels in the water-the Pool company also recommended I do that.
The Pool company is leaning towards iron (especially after the ascorbic "vitamin C" test I did and it turning the spot black and then disappearing) and they have recommended I do the following:
Check the pH and make sure it is b/w 7.0-7.4 and that the chlorine is 1.0 or under. With the pump on, add the "Simplicity" brand Spot Cleaner (after it's been mixed w/ water in a bucket). After an hour, add the "Simplicity" brand Super Metal Control. After another 4-8 hours, add "OMNI" brand Filter Aid. Then, take the filter apart and clean it (b/c I guess the iron is supposed to have been "trapped" in the filter after all of this is said and done).
I hope this sounds right b/c I spent a small fortune at the Pool company service dept. today. :-/