(PICS) Droopy leaves, no growth, purple stems

My plants have droopy leaves, purple stems, and they haven't grown since I first got them on Friday. I am using a 600W sodium lamp. Temp is 77 degrees. Humidity is 35%. I water them once a day using pure R/O water with a pH of 5.7. I added a small amount of nutrients yesterday (300ppm). They are in rockwool cubes. Here are some pics: Thanks in advance for any help.

Over watering.... cut down to every other day watering... or even water once every 3 days... its only in rockwool right?? the roots arnt getting enough oxygen.

Cool..Thanks a lot. Yea I noticed the rockwool cubes are always very damp and seem saturated. Should I wait till they dry out a little before I water them again?

thanks a lot