Well first off you should go pick up a couple buckets from lowes, the grey light proof ones. Order two waterfarm kits from general hydroponics. They each will include a topfeed watering system which you won't be able to use since you are using the 6" net pots, but they also come with water level indicators which you can topfeed yourself then just drain the right amount out. This will keep your seedlings watered till the roots hit the bottom of the netpot where the water is. The water level indicators make keeping up with your water level guess free and it also makes changing the water very easy. Then its as easy as picking up the lids and changing buckets. That is after you drill the holes in em for your airstones. I also us two airstones per bucket. It might be that your seedlings are meesed up b/c they haven't been getting any water. Have you been topfeeding? And as far as your heat issues I would hook that heater up to a timer so when your lights are off your heater is on. And your timming is wrong, you need your lights on for a minimum of 18/6. The lights only being on 16/8 is not enough and your confusing the plants. So order the kits and start topfeeding if your not and rigg your heater on a timer. Also this is just my opinion, but if it were me I would build a scrog net and scrog your plants. Dwc is great for scrog and you'll maximize your yield for your watts.