What's wrong!? 2 Week Seedlings Weep?

I have a drip system setup right now, I have a 1" rockwool cube placed in a drained cup with expanded clay pebbles, everything is working well except last night the stems drastically started growing horizontally. They were growing straight up, now they are falling over... what's wrong? They're about 6 inchs with their beginning two sets of leaves. What problems could there be? Can they have too much water? Should I support them more? Or transplant them to a bigger system? Or will they eventually grow a stronger root structure and be able to support itself again. They are about 4' from a 400w metal halide bulb that is being vented. Everything else looks good except now they are falling over! Is this normal? Should I not be worried? Or what should I do?! I'm freakin' out! Please let me know anything!!!

r u using tap water? too early for nutes, too strong a light try cfl.

The light is 4' away? There are like 0 lumens getting to your plants with the light that far away. If you are still in the seedling cycle you need to use flouriecent lights. Switch to your MH once you have your 4th set of true leaves formed. No nutrients until then. Watch your Ph and don't over water them Rockwool can soak your plants so watch for overwatering.

Check your Ph and make sure it's 5.2 - 5.5 for Hydro.

sounds like to much water to me..... I'd have to see it.. although i am ok with the MH at 4 feet , 4 meters, or 4 miles.. until she starts to show promise (5-14days)

I agree,sounds like too much water ,have had the same problem with rockwool before, or they are stetching from not having enough lumens like zandor says.Seedlings use very little water, because they have a very small root system.Rockwool can become saturated with water quick, especialy after it has been squeezed,like so many people often do after presoak.I would say back of the h2o a little ,and move the hailde to 2.5 foot from the tops ,then lower the light 1" at a time(several hours or a day) from there until the plants start growing out instead of up.
just my opinion , I could be wrong

Ok, I'll get some pics tomorrow, but I've laid off the water, put the light a little closer... (around 2.5 feet) and because it was annoying me... I supported the stem with paper clips to ensure that it was growing up, and that seems to have worked, but when I remove the supports, they slowly go back to the horizontal growth, the leaves are looking perfect and everything else looks good except that strange growth. I believe it may be that the rockwool will only provide so much support for the plant, the rooting structure needs to expand into the pebbles instead of keeping itself contained in the 1" rockwool cube, I put more pebbles near the stem hoping it would provide a little more support. Any other ideas are extremely appreciated and thanks everybody for helping!!! (I'll try to get pics soon) Thanks!!

I could be wrong.. but over watering takes awhile for a plant to overcome.... it is some serious shit as I recall.. you can almost let the cube completley dry... ifthe roots start to need water they will leave the cube and search for it....

I don't understand how you 'overwater' hydroponics? So how exactly does Aqua-culture work? (aka Water-Culture) The root structures are completely submerged in water... isn't that overwatering?