Hi, I use Jacks , its easy and simple just start with half a tsp per gal. and ph it to 6.0 and you'll need some epsom salt when flowering.
https://www.amazon.com/Jacks-Classic-Purpose-20-20-20-Soluble/dp/B001REA5NK?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A3PNUN7H1KV96E
or...