Thats a big swing from 4.5 to 7. I would probably not bring it up so fast. imo you should try bring it up to 6 and see how they react before you jump any higher. Just my 2 cents
Yeah, the first thing you should do is get your run off PH down to 6.0. Assuming you are growing in soil. If hydro, go to 5.3 to 5.5...
It's looking to me like the first signs of nutrient deficiency. And this can easily be caused by having either a too high or too low PH.
So, start with getting your PH correct, and then see what happens from there. If you don't see any improvements, start another thread. People here are happy to help.