Browning, Papery Leaves on Recent Transplants

So I've got a variety of clones from my local clinic and planted them in some Fox Farm. They live outdoors, but I bring them inside at night until it warms up some more, and I put them under a fairly weak light when inside. The sativas are 6" tall, the indicas are still around 4" tall. They've been in the soil for almost 2 weeks and started showing a little damage quickly. They are living in one gallon pots until it's time to go into the big pots. They have spent a night or two outside when it was probably down to the mid-40s. I have been lightly feeding them with General Organics Root Booster 1-1-1. A couple plants are showing this problem, one in particular seems to be a total loss. The browning starts at the edges of the leaves, not the tip, and spreads inward until the whole leaf feels like thin paper.

No signs of bugs or mold, so I think it must be a nutrient or water problem. Thinking it might be nutrient burn, I thoroughly rinsed the soil 4 days ago and haven't watered since, but that didn't help. I maybe overwatered them at first, but I pulled back and still the problem is spreading. I have hard water. Never checked the pH, although I'm under the impression that is less of a problem for soil. But after spending hours in the threads, especially the stickies, I don't see any pictures that look like this. Got any ideas?

I'm still noob-ish, but not a virgin, btw.

Hmm....tough one. My first guess was nute burn, but if you only added that 1-1-1, I would think plants that size would be able to handle it, even though FF is a rather 'hot' soil. Idk man, I gotta think about that one. Can you think of anything that could help? Temps, humidity, PH, wierd drainage rocks,(I used crushed limestome once, and it's a huge no-no. fucked the PH up bad.LOL) etc...?

Well, I am reusing soil from last year. I kept the soil from the one gallon pots and amended it lightly with some organic garden compost to make up for whatever nutes it lost from last year. Nothing else weird in the soil like the rocks. I thought maybe it could be the temps, but it's not hot here. They get direct sun in 65-75 degree weather. It's usually 60 in my house at night, but like I said there were a few nights where they were cold. A couple days they got some cold rain when I was away for work. But it doesn't match up with pictures of cold weather from other threads.

Should I just cut my losses early and get some more clones and fresh soil?