I think your answer may be in what happened to me a few months ago, but first I want to say that PH should be going down, not up.
At any rate my Ph was going down unusually fast, and so I added PH up, several times... and by the time they were done, they certainly we not looking right. It turned out to be my ph meter. PH meters are very sensitive things (so I've learned), and the bulb needs to be kept moist (wet) and clean. In may case I was doing that, but it turned out to be the PH meter.

SN