I use
Promix and have used it for over 3 decades. I find it impossible to screw it up as long as you don't overfeed. I don't really add anything other than composted manure, wood ashes, and some timed release fertilizer mixed into everything. Feed every 7-10 days (or more if you think your plants need it, but I never did) and you will have a great grow without PH or other issues. I know that you have experience, but mistakes can happen...as you have found out. I'll be more than happy to provide any help with a
promix type of medium. I haven't used anything other, so I can't comment on Coco or whatever those little round balls are. Water once a day, feed once a week, and you are good to go!