Borax will raise pH, baking soda will raise Alkalinity and I believe that Soda Ash will raise BOTH pH and Alkalinity so it looks like you need Borax if you want to raise your pH.

As far as the CYA, did you do the test the same way in the same place both times? I did a CYA test a few weeks ago that game me a reading of around 40 then I did a reading a week or so later that was only in the mid-twenties but when I thought about it, I did the test in two different places and I didn't pay attention to the amount of lighting available in both cases so I think that was my problem. Lighting will affect how well you see the black dot so that's important.

Peter