Thanks so much for your reply!

I tested my tap water, and I got a Calcium Hardness of 170. I have to admit, however, this is only the second time I've done this test. The directions say it should turn from red to blue, but to my eye, the colors are more like hot pink turning to blue with purplish particles floating in it. Does that sound right? That said, I'm an interior designer, so my definitions of color are usually a bit more specific that most.

I ran the CYA test again, using the dilution method you suggested. I had to go to the two parts distilled, one part pool water test. It just reached 100, so my CYA must be around 300. Yikes.

I filled out the pool chart entry form - I'm row 101. I use minimal products in the pool, mostly due to what I've read here:

Products used REGULARLY:
--Kem Tek (Trichloro-s-Triazinetrione 95%) 3" tabs in a floating dispenser
--Liquid chlorine (sodium hypochlorite 10%) only for a green pool
--DuPont (Trichloro-s-Triazinetrione 93.5%, Copper Sulfate Pentahydrate 1.5%) 3" tabs in a floating dispenser - I used this ONLY over this past winter, as they didn't seem to keep the chlorine level high enough in warm weather, plus I have no idea what the copper sulfate is)

Products used OCCASIONALLY:

--Muriatic acid (used recently to fix high TA, but generally only occasionally needed)
--20 Mule Team borax
--Baking soda
--Shock Quick 1 lb. bags (Trichloro-s-Triazinetrione 40%) Sometime these packets come free with the tabs, but every time I've used them, the algae only gets worse.

I've never used the cal-hypo that you mentioned, at least not that I can recall.

Thanks again for all your help!