Leaves yellowing, purple stems, brown spots. HELP Please /first grow speed auto

Hey there Supermegadjj, these plants got stressed from all the yo-yo-ing up and down with the nutrients and the pH. If you want them to bounce back it's important to reduce the stress as much as possible, especially during flower. Try reducing your light schedule as much as you're comfortable with. Keep spraying cal mag once 1ml/L , increase the feed to the correct level and try to keep a nice constant environment for the plants. Hope this helps ! 🚀