first time grow (any help really appraited)

so i got my plants like at about a ft tall growing about 1/4 inch a day all i have done was water them with rain water i have saved up should i use nuits? if so what kinds? also the guy that i got them from gave me them in 3 liter bottles full of pearlite should i change them if so into what? they look really healthy do i need to trim them?

lets see picture
and stop using rain water get distilled

im about 3 weeks in now i changed my lighting now and have started adding nutrients i use 1 litre of water ph at 6.2 then add a and b formula then 4 mls of rhizotonic to help them route properly im using a 600 watt grow light and fan on 15 min on 15 off on timer lighting is on 18 hours on and 6 off i usualy turn off lights at 1 pm til 7 pm then turn back on can you put any pictures up so i can see thanks widdow sensation