Skimmer control at high pH

Thanks for reading my question.

I'm using a co2 scrubber on my skimmer.
Most of the time my pH stays well in acceptable ranges, but if I open my windows my pH get to high due to overscrubbing.
I'm talking 8.7+

Now, if I want to program my p4 to shut of my skimmer if pH is rising above 8.6, how do i do that?
I'm not sure how to use the programmable logic for this.

My skimmer is on my 3th socket at my PowerBar.

Thanks in advance

Forgot to mention,
To shut my skimmer off for one hour, so that it will run after the pH has come down a bit

Never mind, got it working now..

Excellent!