According to my calculations, it will take 7.6 cups of Muriatic Acid to lower your pH from 8.0 to 7.5 given your TA and CYA levels and your 27,000 gallon pool size. Carl's advice is, of course, spot on in that adding one quart (4 cups) and seeing where you are at is prudent. I would be curious to know how much acid you do end up using, though your pH measurement of 8.0 might be 8+ since that could be the top of the range of your test.

By the way, lowering the pH from 8.0 to 7.5 by adding acid will also lower the TA from 130 to 121 (i.e. measures as 120). That's part of the reason says to adjust the pH first since moving pH ALWAYS moves TA as well (there are technical reasons for this that I won't get into here).

Richard