I agree about the light being to close to your canopy. I usually put my lights up as high as they go and let my hogs grow into them, and they will! Just trust me! I also encourage u to try out Silica Blast and Cal-Mag they are both from the Botanicare Advanced line. If u use proper dosages of both it should firm up your foliage a great deal. Dont worry about giving your girls too much, the fact is; is that Cal-Mag is a supplement not a nutrient, it has many trace elements/minerals so it doesnt feed, same as silica blast it doesnt feed either, plus plants only take up what they can absorb. Silica Blast goes into the cell walls of the plants and stiffens them up it also makes it easier for the plants to store and maintain water to keep em from drying out. Now if your leaves are curling DOWN and buckeling as well; that is usually because the plants are cowering away from the light. This is why I put my lights up to the top of the room, I would rather have my Girlies REACHING for the light as aposed to Running away from it. Also keep this in mind, that most reflectors BRIGHTEST spots are around the outside edges; and not directly under the bulb....
Good Luck and Happy Farming