Plant problem? Yellowing and drooping

I have 2 jmc plants right now and the first one is 6 weeks into veg and the other is 3 in veg. I'm using a 1000 watt meh bulb in an aeroponics setup.. Using 6 mg of aerogarden nutrients (3mg each). Water ph=about 5.5 Both plants are in the same aeroponics system. The 6 week plant is getting what looks like it is a nute def...( yellowing of middle and bottom leaves) but the younger plant seams to be fine but is getting the same bytes and ph. The younger plant is seems to be healthy but the leaves are dropping (temps 72-80f and humidity is 30-55%)