That's a bummer about your PH meter. I've often wondered if both my PH and PPM pens are telling me the truth, but once you get a system down it doesn't matter if they are off, as long as they are consistent.

What's a muffin fan? Is that the little computer-type fan I see in the photo? And is the hood open and the hot air blows out the bottom?

Looks like the reveg still has promise. It is normal for some leaves to get yellow and fall off. That's why you want to make sure you leave enough leaves when you are cutting the plants back. Also if your nutes aren't quite right she can eat herself to survive.