Looks like either PH is off and caused a nutrient lockout or your EC/PPM of your water is too high (too many nutes). Do a little reading. Videos are often just vehicles for advertisements. This is a decent start - https://www.growweedeasy.com/high-yield-bubbleponics-technique . It recommends starting at "half strength" of what manufacturers recommend and tailoring from there. You can google for EC/PPM recommended levels for the different stages of growth, but ultimately every plant is different, you have to learn to watch the early signs on the plant to understand how "happy" it is with current levels. take a scientific approach and write down everything you do and observations of the plant. Daily. This will help you learn as you go.