I don't grow without it.
It's got either humic or fulvic acids (can't remember which) which act as chelating agents to help the rest of your nutrients be assimilated better at a wider nutrient range.
Full of amino acids, to boost terpene and oil production.
Also has Bacillus to fight bad shit in your res, boost roots, and helps your plants take up nutrients better.
Healthier plants, larger yield, higher potency, and better smelling buds.
Smells a bit, but it's BOMB shit in Hydro.
Expensive as hell but worth it.
Use it at full strength. Don't go over, it's potent.