using a ph pen

i have grown forever however have never used a ph pen.i checked runoff and got a 7.89--i uderstand thats not good so how to fix and where should it be and how to do this right in promix

Runoff pH cant tell you much. 7.8 isnt that bad. Its probably a bit of salt build up that got leeched out with the runoff.

But that isnt the same as the ph of the promix in the pot.
Make sure your pH is good going in and be consistent with that and a good amount of run off to prevent salt build up.

what is best going in--6.5 or 7?

tryin to figure this out--water phed to 7.2 goin in and tested overflow---5.6 this dont sound right ,any help would be appreciated

There are many opinions out there but usually between 6.0 and 6.5 for promix so just pick one and watch the plants. I agree with Gq, the only thing I really care about when measuring the run-off is the ec.

Always be sure your pen is calibrated.

With promix I use a pH of 6.5 - 6.8 on my feeds.

Stop worrying about runoff pH. Is there an actual problem with your plants? If there isn't leave them alone.