Quote Originally Posted by need4weed
thats what they do at night
Yes, but they're not supposed to.

Do you have an air stone in your reservoir? What is the temp at night? Slow the watering at night. If you do it 3 or 4 times a night... try just once or twice... but keep the water flowing as you have been if they look good during the day. The plants can't process all the water they are receiving without the light during the dark periods.