Falling leaves lots of them

Hello I am now growing 6 ak48 four days ago I went 12/12 after a month of 18/6. Today I noticed that 2 of the plants started tipping down and theyr leafes are drying. I soak them every 2 days and I use a 300w hps and I don't use any nutrients. Here are some pics http://i289.photobucket.com/albums/ll231/GreenOrange88/24062008196.jpgThis is the first one and the next 2 pics is the sec one http://i289.photobucket.com/albums/ll231/GreenOrange88/24062008201-1.jpg http://i289.photobucket.com/albums/ll231/GreenOrange88/24062008202.jpg
Whats wrong ?

Your soil looks pretty wet... I would say theyre being overwatered.... Hard to bring plants back once they've crossed a thin line, but lay off the water for a few more days... Make sure to dig your finger a good couple inches into the soil to check for moisture. If there's any moisture down there then dont water.

Might also try getting a Moisture Meter from your local nursery. They're always helpful when youre unsure.

I concur. It looks like overwatering to me. Let it dry out a bit before watering again.