troublesome plants

Hey gc! first time grower of anything I've been having some problems....please help me. Thanks in advance. Here's some info and pics.

Rdwc with clay pebbles 30l
Indoors
2 x Vast and fast and budda kush
Around 30 day the bubba kush is around 15 day
1 400w hps air cooled
300 400mm away from light
Green planet dual fuel and general hyro cal mag I change once a week
Abit over half strange 1ml calmag pre L
Ph 5.9 ec reads 222?
30 highs and 14 lows
20 to 45% humidity
I didnt ph my water after a change about weeks ago it was like 10hrs maybe more I flushed it with just water for 2days started calmag and nuts little by little

I topped one then I dropped something on it and lost a main branch

I thinks its alot of things ,could I have guidance for further grow I really want master hydro thank gc