Crispy leaf tips, what could this be?

Ok, well my first grow went well without this issue, but since I transplanted and put under HPS lighting I noticed the leaf tip on this plant looks like it is dying, otherwise the plant is doing great. When I transplanted I did get rid of the old soil off the roots, not sure if this could have done anything.

Conditions:

Watering once a day (not alot of water)
HPS light 17 inches from plant
Temp: 88 Degrees (with fan circulating air)
Humidity: 50%
FFOF soil
Lightly misting the top of the soil a few time a day to cool em off a bit.

I don't think it has anything to do with the grow medium or nute burn since FFOF is great and im not using nutes. Maybe lighting changes stressed it? Transplant stress? I know it is a little warm in there, but my other plant is not showing crispy tips, pH problem (but I doubt it) I appreciate any input that the pros might have with this.

Here are a few pics:

http://img413.imageshack.us/img413/4733/dscf8047o.jpg

http://img405.imageshack.us/img405/8708/dscf8049n.jpg

Looks like slight overwatering.
The larger the container, the more difficult it becomes to regulate the moisture. Since cannabis prefers a wet/dry cycle, perhaps skip a day between waterings.

Alright, I will hold off, and thanks for the help I appreciate it =D