I need some advice. I have a NFT setup with 60 strawberry plants. I put them in yesterday. I set the PH carefully to 6.0 and mixed in my nutrients. I'm using General Organics nutrients. After I finished I checked the PH again to see if it would change it was still 6.0. I was surprised to see my PH is now 7.7 this morning. Should I add in some PH down? Also any tips or tricks or advice would be appreciated on my setup.

Just wait and see how they grow. pH tests other than ones done by a lab and taken from samples collected carefully and methodically can be all over the place. If they grow well, leave it alone I say.