nutes: Grow More 20-20-20 ( 4000 gallons = $44 bucks and dry theres no dry shaking or stupid shelf lifes and this stuff is meant for cold water solubility, its awesome ) + 60% fulvic acid for cheap ( custumhydro) , a few bucks gets you kelp ( if you pick good brands and not water ) , than epsom salt and calcium nitrate ( theres so many things he could get but i wanted a basics line, it would work perfectly and growing is 30% environment+ of the end result , people pay way too much for nutes!)
that kind of nute plan would work and thats why so many ag use it, cheap and simple all the way down. grow more main rep recommends its for the beg stage veg stage- end stage veg, but i wouldn't be suprised if you tried plants full stage 20-20-20 ( since npk is npk) = easy peezy & 1 staged and 4,000 gallons ( just need to follow the staging of how to add the dry amendments so its stable)