Leaves are turning colors...Help

I've been flowering 4 girls from seed. At the beginning of today's day cycle I noticed the leaves are turning a dark green to light brown and they're curling a little towards the light. But, I've heard that purps can show up if the temps are around 60 during the nite cycle and thats about what they are b/c my set-up isn't insulated and its cold in my basement. Could they be in turning already or am in trouble?
Any input is appreciated.

Sounds like too much fert. Any pics?

No i'll try to get some up here but, it can't be nutes...I haven't used any, I've just been feeding my girls tap water. But, even the stems to the fan leaves are turning a dark purple...I have no clue haha, I'm learning as I go.

nute burn, are the tips drying out too?

No, they don't seem to be...2 of them got a little light burn a week last week but, i've kept the light pulled back since then. And like i said, I haven't been using any nutes, just tap water

Need pictures. Also include as many details as you can.

Have you checked the pH of your tap water?

No, I don't have a ph tester...

If I can get some pics up here in the next day, that might help. I'm probably taking tomorrow off b/c where I'm at we're getting swamped w/ snow rite now... So, I'll spend the day getting some pics up and figuring out whats wrong w/ my babies