Well from the little that is on the picture, it seems like your light is probably to high. I would move the light down to about 18" away from the tops. Personally I prefer to veg with MH, but that is a different discussion
I say u go with a closer light source, and you will see that internodal growth tighten up. If you are worried about temps.. try an air cooled hood and or a fan pointed up into the hood from the ground cooling and dispelling the heat from the bulb. at least they look healthy. You could always train them at this point to mitigate the stretching, move the light down and have compact growth starting with the new shoots off of the trained main stem. Good luck