Raise my alkalinity

Question
I am in the process of setting up a 20 gallon freshwater aquarium, for my one
betta fish, that had to be transferred from a 10 gallon to a 1 gallon.  The
conditions in the 1 gallon are not good now with ammonia at .5ppm,
(gh)50ppm, (kh)50ppm, and (ph)6.1.  My tap water has a (gh) of 75ppm,
(kh)40ppm,(ph)7.6. I did about a 30% water change yesterday and treated the
replacement water with "Proper Ph 6.5".  What can I do to safely raise the
alkalinity of his water?  I would like to set the 20 gallon up with a more
neutral ph of 7.0.  Any advice would be greatly appreciated!  Thanks in
advance!

Answer
Hi Gary,
Proper PH has a few products.
They have Proper PH 6.5. 7.5 and 8.2.
You can use the 7.5 to give a nice PH, or you can simply add regular baking soda at the rate of 1 teaspoon per 5 gallons until desired PH is reached. It's cheap and that's what I use on my prize cichlids.
Just remember when you do water changes to add back just enough Proper PH or baking soda based on how much water you replaced.
OK?