hey guys i'm having a few probs with my plants hitting a wall around week 7 of the flowering period....... i'm operating a 4 tray SoG system with individual tanks for each tray, i run 1.6 EC on tanks 2 & 3 and an EC of 1.4 on tanks 1 & 4..... ph is usually between 5.5 and 6.0......i use canna...