wow. you are asking for help from mind readers? ok to help things we need to know
r/o water or tap?
tap water can be very hard sometimes. will fuck up any store directions
what is your e/c ? ph?
too high, it is lock up. PH is the number 1 misdiagnosed problem. you mention 6.3 that is ok for soil. High for hydro.
what is your res temp?
you want 65-75 range. any more or less is dangerous.
what is your room temp?
again too hot or too cold will effect them
what is your grow media?
some media the roots heat up or chill easier than others. Over/underwatering also can be issues.
what is your nutrient base?
most high end nutes ask for way too strong a base on their directions. make sure you are using soil nutes for soil and hydro for hydro.
I do lots of grow room consultations. So many little variables that can fuck shit up. Without a person being able to walk into your room and look, you have to give info info info ! Limit the variables so we don't waste our or your time eliminating problems that you don't have.
also pics are worth a thousand words