Plants slowing down right after germination

My first set of plants are doing great and grew an acceptable pace but by second generation has slowed down immediately after germination.

They grow fast until they get their second set of leaves(3 inches tall) and then they just stop. I have adjusted everything from temperature to soil, water pH, amounts of water. I got the temp down to 75F in the room and the lights are within 2-3 inches of the tops of the plants. i use 4 150w replacement CFL bulbs for vegging and they are set for 16 hours of light a day.

The only thing i havent tried is increasing the number of hours the lights are on per day. Would this have anything to do with the slow growth? maybe 16 hours is too little for this strain? I read that if a plant thinks its getting too close to 12/12 it will slow down to save energy for flowering.

16/8 or 18/6

don't be a mother duck. just let them be and it'll be fine

that helps lol. I left them alone for two weeks before i started messing with their environment last week. its three weeks now and no changes. im not mothering them.

if there's no leaf growth then its likely there's no root growth either. switch to 18/6 or 24/0 and add some nutes. if it's in organic soil and you use chlorinated water you could be killing the microbes that process the organic matter ito usable nutrient. hard to know without more info though

thanks a ton. Ill switch to 18/6 when i get back tonight. the soil is MG mixed with compost and humus soil with some perlite and a little sand. I use filtered water since it brings the pH down from very basic to just slightly basic. 6.3