I'm growing 17 plants now under a 400W MH/HPS switchable ballast. The plants are 8-10 inches tall right now in the fifth day of 12/12. Gender is starting to show. I hope to flower 2 of each of these strains. Bubbleberry, Power Plant, Blockhead, Special-K, and Skunk#1. I'll post a picture of the growroom below, but I have a couple of questions. The PowerPlants (4) now, all seem to show signs of the leaf tips curling up slightly. All other strains are very healthy, so I was wondering what would be causing this in this particular strain. Also, I originally ordered Sweet Tooth 3, yet they were out and sent me Blockhead. Does anyone know anything about this strain? I was expecting a strong indica, but by leaf structure, I think its a split. I would like to know a little more if anyone can help. I also have a hepa filter in the growroom, because I was told it would improve the tast of the Bubbleberry. Is this a myth, or will clean air actually improve the taste of the bud? The picture is about a week old. I'll post new soon.