A few days ago I performed the Ascorbic Acid cleaning on my pool. Before the test, I made sure my chlorine was at ZERO. Also, my pH was roughly 7.8 and ALK was around 150-200. The main thing I have had to deal with all summer though is that my CYA has been over 100. Anyway, on with the Ascorbic acid cleaning. I ended up using 3lbs. of acid (mainly because i'm impatient and not sure what i was doing) for my ~10000 gallon pool and about 20 oz. of Jacks Magic The Blue Stuff Metal Solution Too. I was trying to follow Mbar's instructions. Well, the past couple of days, I have been slowing bringing my pH and chlorine back up, using borax and bleach. My pH now reads about 6.8. Alk is around 150. Free CL is reading 1.0 while combined CL shows about 3.0. The biggest shocker of all though was when i tested CYA. I was hoping it dropped a little bit after all of this, but I couldn't believe that it reads 0 - yes ZERO! I would've done the test twice, but i don't have enough Stabilizer Solution left. I know i did it right though - I've performed this test several times this summer. My pool water has a nice green tint because of the new algae growth on the walls and floor - I haven't vacuumed yet - but the water itself is very clear when I do the CYA test. I can fill the test tube to the rim and still see the black dot at the bottom. Does anyone have ANY explanation for all of this? I would say that I might need to add CYA now, but i'm still skeptical! FYI, i'm using the Aqua-Chem 6-Way Professional Test Kit from Wal-Mart.