Beginner grow Aerokit

Week 1 of veg, although only had one week from germination these are about 2" in height and starting to show good root production, they have been in the tank for 3 days now and are looking fine, I cracked 8 seeds that were my freebies from London seed centre, (thank you), although 2 of my DR Ray DR Lemon didn't crack and the third one I inadvertently washed down the sink, ffs.....aaaaargh. Girl Scout and Skywalker cookies were straight out of the starting gate and look like nice strong sprouts, they shot up in the space of a few days, nice and tall and straight, they were started in a tissue blanket and then transferred to rock wool, before being put straight into neoprene collars and into the aero kit. I just give them PH balanced water for a few days and then added half the recommended nutrient amounts into the tank along with half the amount of rhizotinic recommended, didn't want to scare the shit out of them so soon. I had my 400w sodium in there for one night, nearly fried the little buggers, changed for a 125w MH bulb now, which runs a damn site cooler than the hps. but figure I can use the HPS for bloom, and remove the extra heat by adding a Flexi hose out of the cellotex room into the main tent and out the carbon filter. which is a nice strong extractor (it creates a small vacuum inside my bud box, the sides of the tent concave inwards), I generally turn off my tower fan at night to bring the temperature back up as its usually warmer during the day and colder at night but leave the extractor on otherwise it gets wet with condensation. Update, I did buy a new 600w HPS with new ballast, but this I put in the tent with the 9 that are now in flower and moved the 300w led to the aero tent, they seem to be responding nicely so will just monitor as I go.