Can you take some pictures with your HPS turned off so that we can see the true color of the leaves...and then, how often are you watering and how much water are you giving when you do water? I can see you are using an HPS bulb which will work although it’s not ideal for veg so if you have a metal halide bulb your plants will do much better with that light spectrum. Tell me about your watering and feeding Schedule and we can most likely figure out what exactly is wrong. I’m almost positive it’s from either under or overwatering. Also, your plants don’t look very bad at all, so I wouldn’t worry to much. You just need to fine tune your watering habits. Sent from my iPhone using Grasscity Forum