I have a few arugula plants with some other greens in a recirculating DWC system. They are under a 400 watt metal halide in a tiny room with an air-conditioner set at 60 degs., the light is on 14 hours a day. They are about 4 weeks old, and all was well until this morning. I changed the solution last night and this morning they seem to be wilting a bit. The older leaves are curling under sort of the cannabis does when over fertilized. The leaves seem very soft but I assumed thats just the way hydroponic greens are. This is my first time growing arugula and lettuce hydroponically. I'm using RO water and a General Hydroponics series that is apparently unmeantionable with Floralicious plus and Cal-Mag. the solution is about 700ppm and about 6.0.