Yellow / brown spots on leaves

[Weebay]

Sorry but what is EC? how can i answer your question? =3

[gbauto]

EC refers to the concentration of the nutrient solution you're feeding the plant.

[Weebay]

I am using these fertilizers: https://www.eurohydro.com/dualpart-coco in addition, i'm using https://www.eurohydro.com/bloom-booster
since i changed i can clearly say the burn marks and the clawing have been coming a lot more slowly than before, but its still been progressing this week.