Northern Light auto (First Grow)

Update 12/8/2021 Keep on Rocking!😎 having a hard time getting the climate at a constant lvl. doing the best I can with the equipment I have🙌 Update 15/8/2021 from day 43 on i've started to add Calmag to each watering. but after a couple of day's it seems new leaves are still getting brown spots. not really sure what to do.. The nutrient schedule I'm using 1/4 of what is recommended by the Bio-bizz schedule. all plants are given the same amount.. 3 of them are showing some deficiency's and 1 plant is looking really healthy. Update 18/8/2021 Hello Folks.. pffff deep breath My plants are really suffering.. only 1 is doing a really good job. the others really look sick. leaves starting to yellow cetting curly and crunchy.. I did pluck away most of the dead leaves but at this rate there is going to be nothing left 1 one week. I have no real clue what's going on as it's looks it could be several things. it really feels i'm constantly running behind the facts. I know this is my first grow and all and every decision I make will teach me a great deal for the future. Today I ordered a digital PH/EC/PPM meter so I can actually see what exactly is going on and make decisions from there. I am afraid the PH of 7 really blocked out the Nudes that have been given but I am not really sure so let's wait like 2 more days so i can start measuring stuff. the past 2 days it only flushed the plants with water at an estimated guess of 6PH. but the crappy analogue PH meter that i put in the soil still tells me the the soil has a PH of nearly 7. What I really don't understand is how 1 plant really doesn't show any symptoms while i gave every plant the exact same water/nutrients etc. Well fingers crossed. what a hobby🙌💪