Dark green almost purple top leaves

[tflr15]

I have some clones that have been growing for about a week now. Their about 5 inches and had been looking healthy until the new leaves at the top of the plant started turning purple and the sides of the leaves are curling up. Is this bad? I grow with soil and have a 400 watt hps about 2 feet from the plants. It get 75-82 in the room. What could be the problem?
heres a pic
http://i28.photobucket.com/albums/c2...5/100_0480.jpg
also i used some fer on it but i dont think i used that much at all. It was less than half a teaspoon.

[Ganja Guerrilla]

are the clones rooted yet?
Its difficult to see the purpleing, were they purple before or is this new, if not in the plants genetics, purpling is from phosphorus defeciency, wether it be from lack of feeding , PH lockout or temps below 57F
a purpleish color can also be the first sign of a burn about to turn redish brown

they look like the color between the viens of the leaves are lighter? or is that just a photo flash thing?
the curling up can be caused by magnesium def and also is accompanied by lightning in color between the viens
the curling can also be caused by heat stress/excessive transpiration

1. hydro, soilless or Soil & brand name of soil ?
2. PH of reservoir solution?
3. PH soil runoff?
4. PH of water?
5. Age of plants?
6. What Fertilizer, dosages, and frequency?
7. lites, wattage & proximity to plants
8. Light cycle. 24/0,, 18/6,, 12/12?
9. In light cycle how long?
10. Room temps or reservoir temps