San fernando Lemon kush,widow , Critical

I have started to use nutrients on the plants in the second photo. In this part of the diary i was watering with little water and that has affected the growth of the plants. The pH was incorrect and i raised it to 6.1. 1 of the san fernando lemon kush died R.I.P This week the plants look very healthy, they only needed water and a little more dose of nutrients. In the second picture you can see the coco so dry because i thought i was overwatering the plants, but i investigated a little and i realized that it is very difficult to over water plants in coconout and more so on aeropot pots since it dries faster. I transplanted the plants to 7L pots (not the last size of pot i will use) and i'm mixing mammoth and roots Excelurator in every watering. Im watering once or twice a day 200ml with nutrients and 50-100ml of only water in the second watering.