Yes, you maybe right. I gave them in the beginning just 0.6 EC with RO. Then i changed to tap (0.5 EC) + epsom (~0.2 EC) and there was only room left 0.5-0.6 EC for base nutes. The runoff EC was climbing so slow, but nowdays it is 1.5-1.6.
I was angry last week and i hit them tap+epsom+BioNova A+B till 1.8 and they exploded in growth.
But they don't liked it. I suspect tap water, because some of my leaves become whitish filmy (veil?). Sorry, but i am learning english too due this hobby... It is very difficult to express myself. I can read everything but speaking and writing is hard yet
I will go back to RO but i can't decide which nutes i use. GH 6/9 or BioNova Coco A+B.