Growth from seed

Recently I started some trainwreck from seed. They sprouted in only a couple of days in rockwool with 100% success. Later that week I transferred the rockwool to my DWC system and have been monitoring several times a day but am not seeing any significant changes good or bad. I still have basically the starter leaves. Here are the specifics of my setup.

DWC using ph 6.6 tap water constant temp 67 degrees with water level to the bottom of netpots no nutes
Temp in grow area fluctuating from 65 to 75 depending on the time of the vent cycle
400watt mh at about 2 feet 24 hours.

I realize the the DWC is not doing much if anything at this point but I wanted to get it ready for when the roots descend into the solution. So daily I am dipping some water from my reservoir and trickling over the rockwool to make sure it doesn't dry out. Is this slow or am I just impatient. I haven't grown in 10 years and want to make sure Im on the right track. Also I have 4 plants in a 3 x 6 x 8 room..am I going to outgrow this going traditional or do I need to consider some LST?

You didn't say how old the seeds are, but your PH is too high.
Aim for 5.8 or so.
Also, if you put this question in the hydro/ aero section with more info you'd probably get more answers.

Do as bakatare said with the ph, and just give em time. Its gonna get cramped in there though with four, either switch to 12/12 when they are about a foot tall at most or cut it down to two plants. Your seeds females?

your using an hps on the pic, not mh. no need to ph water since there no nutes in it. looks like might put them to early into the dwc. but dont worry they will go eventually next time wait until they are bigger to put them in. your in right track though.

also add mylar or white film or paint white on the walls,

As already said, change that PH or else your gunna get nutrient block out. And you gotta wait first 2 weeks are slow after starting nutrients you will see them explode (in a good way) hope that helps