I use Advanced Nutrients 3 part mix in a soil basically made the same as promix.
PH is supposed to be between 6.3 to 6.8.
I'm reusing my soil this year that I grew in last year and my plants aren't doing as good as others in new soil.
The PH wasn't the problem though because I PH'd last fall and it's close to 6.5
It's probably nutrient salt buildup causing nute lockout.