chemical levels

[ctpool]

I have a quick set pool. Last year I used shock once a week and kept 5 chlorine tabs in a float. This kept water in good shape. I used testing strips, all levels would be high or low together. Now I have a mixed test. Everything is good except ph is low. How do I fix just one level without getting the others too high?

[PoolGuy]

soda ash, or baking soda