If you use the PRO MIX...you dont need to add a damn thing to it really. I used some bat guano for my nitrogen in late veg.....

I think I fertilized 3 times her whole flower period with some shultz cactus ferts. And I did it very lightly and everytime I did it, I got just a lil hint of nute burn.

Some sites that sell it for MJ say you dont need to add a single thing....

Macronutrients prevent the damage that Miracle Grow willl cause plusit has a biofungicide built in.

I too am prepping my next grow and gonna do some side by sides on Pro Mix and some Ferti-Lome.

The only thing I can say about the PRO MIX is keep it wet. It is like a sponge and will dry out EVERY SINGLE DAY with good lighting after about 3 weeks of growth. Even before then, it will need to be checked daily.