then i would say use it if you got it, but its not neccessary, i grow great plants, all i use is
promix hp with myco...and some 12-16-33 dry tomato ferts, some cal/mag(my tomato ferts have zero cal/mag in them...) and a 0-52-32 bloom booster...i keep it simple, my plants love it...
needless to say i started out on dry ferts and alwys did good...took a break for 4-5 years....came back, tried AN whole line up, H&G whole line up, some GH, some Canna....and i always had problems with my plants...now im back to dry ferts and im doing good again...