Dwc drip/aeroponics/bubbleponics lots of pix first timer

This is my first time growing ever. I am growing 2 og x grand daddy purple and one LA master bubba. I got these clones a week from today and they are just surving. I am keeping the ph around 5.9 -6.4. The room temp around 78-83 and humidity around 40%. I am not sure the reservoir temperature but i do keep frozen water bottles rotating throughout the day to keep it cool. The last res change my nutes where at 390 ppm's. I am currently using distilled water from walgreens. I am using fox farm grow big and big bloom with a little hygrozyme and superthrive. I am not sure if i could use hydrogen peroxide but if someone could answer that would be great. Also some of my leave are looking burnt and one root was looking a tad bit brown but the rest are looking white.