Totally Random, mostly.
So how are you bringing the pH up? Don't add your pH buffer to the tank directly! Mix some in a separate container with tank water and add it in little by little. After you add some, let the tank go for a good 30 min - 1hr at least before retesting the pH. Somehow, I have a feeling that what you do to your tank will proportionally affect mine... strange... are you a wizard?
I did not add the buffer directly! I mixed it into a small container of tank water then added in a bit at a time. I have not yet retested it! Will do soon. I am indeed a wizard. A wizard of all things awesome and useless. Bwahaha!