Can you elaborate on pro mix? You say it's like coco does it have special nutrients? I'm interested but hesitant.
It has no built-in nutrients or amendments (except for some lime), so it's like coco in that regard. It's just a 70/30 peat-perlite mix with myco and bacillus, plus some lime since peat has a lower pH. Peat has a bit more water-holding capacity and a slightly higher CEC (nutrient/ion holding capacity) than coco. But, when you use it, everything comes from your feed and you have to feed from the start similar to coco / hydro.
Since I'm only using 3-gal pots, I went with peat because I wanted to increase water retention / reduce time between watering.