5 Gal Dwc Grow Going Bad

SOMETHING IS WRONG WITH MY GIRL-her primary leaves are dying suddenly! Any help/advice would be awesome, I think she can still be ok!

12 hours after I had last checked, the ph was fine at 6.0, the temperature was 77 degrees farenheit, and there was no nutes because I had gone with 1/4 strength 2 days before but decided to flush the roots when tiny grey patches appeared on the first set of leaves.
Otherwise healthy seeming. Responded well to the nutrients besides the grey spots, but those might not have been caused by the nutes.

I'm curious to see what the cause of this is. I have 6 plants with the same symtoms in an aerogarden. I started with country well water but after noticing the brown/rusty spots speading on the leaves I replaced it with distilled water with 300ppm fox farm nutes. so far so good.....hasn't moved to other leaves yet. ~Outlaw~

well I suppose you are lucky. The spots took about 4 days from grey almost nothing to blossom into what you see here for me anyway. I was using distilled water also with genaral hydro nutes.

Is this what it looked like at first??