If you want to bring up the ph, use Borax, it won't raise the alk. much, if at all. But since you have low alkalinity - you want it between 80 - 120, you can add baking soda - it will raise both ph and alk.
Here is a link for the bleach calculator, click on the top more calcs) and there are other calculations, there is one for ph and alk

http://www.hal-pc.org/~mwsmith2/BleachCalc262.exe