If you glance at ACTUAL Fox Farm feed schedule you can see the EC / PPM they suggest ( which are way too high ) .
If running their “ trio “ ( grobig , tiger , big bloom ) …. Big bloom is the organic of 3 - but used to keep myco in medium humming ( to weak of a feed to use alone ). Trio is best thought of as a 2 part with myco supplement- GRO big for veg / Tiger for bloom .
Their nute line is very concentrated thats why it can burn your shit up if you are not careful.
I always start around a 1/4 strength instead … monitor plant tolerance to it and tweak if needed ( as some strains are feed pigs ).