Rising pH
Are you using the all bleach method? If you are, that may be why it is climbing.
Anything that you add to the pool, can change the pH depending on the pH of what you are adding.

Bleach, sodium hypochlorite, has a pH of around 10 or 11, very alkalotic, so the more you add, the higher your pH will go.
I have found that in my pool which is open all year round, I ONLY ADD 2 chemicals!!!!!!!!

Bleach and Acid.
Bleach for my source of chlorine and acid once in a while to bring the pH down.
That is it. Once your pool is "tuned" it can be that simple.