12" might be a little too close. Looks like most of your curled leaves are on top of the plant, so I would raise the light a little. That's also not much of a temp swing...Can you get it a little cooler at night....70f at night would be much better.
And maybe just give them water without nutes for a week Just calmag if anything AND ph it....a little on the high side if anything. The bottom of the plant looks OK...You can bring it back.