Turning purple and starting to droop

If anyone could quickly help me, i have posted a pic up of my plant a few weeks ago and you all said it was looking good. Now i have put the 600W HPS on it and its starting to go purple its very purple on the top 2 branches down the leaf vains and on a few below. Its also drooping a fair bit and havs a frew dark and light green leavs and it also has purple lines up the whole stem of it. What could cause this its not becase its to cold as its at 24c and im only using nutes every two days

wasnt this posted in general forum as well?

as i said before, shouldnt be giving it nutes every 2 days really. and need pics

PHOSPHORUS. Maybe magnesium too if the leaves are curling under. You definitely need to up the P and keep the K, lower the N. That is definitely Phosphorus. I do not know an ammendment for magnesium except that there are supplements for it from Down to Earth, General Hydroponics, and a few more. They also have other micro nutrients that will help a lot.