Leaves curling

hey there Flavaz, welcome to 2020 what a time to be alive ! Growdiaries is great because of all that data you can input, so go ahead and do consider getting a therometer for in soil and outside measurements, i got an in-soil one for $10 and a laser thermometer for like $15 that way you can measure the soil, ambient and leaf temperatures giving you a perfect picture of where you're at. The roots way to go about figuring out if there's a heat problem is to put your hand under the light and wait a bit to see if your hand starts to feel like too hot, if you can keep it under the light no problem for a fair amount of time then it's not that, but if it is too hot you should be able to tell. Several things you have to do under HID to get the heat under control , first get a "cool tube" if you can, second get an adjustable balast so that you're not blasting 400Ws on baby plants, that should help big time. The next thing you can do is get a small "evaporative cooler" which you can find for under $50 , this is some kind of "AC" that uses water evaporation to stabilise your grow space around 24-26°C and 50% humidity which is kinda perfect actually. Too me it looks like a heat issue but sometimes little guys just kinda grow like that , so it could be that too, let's see. Hope this helps ! 🚀