So one of my customers always said that the hydro store is just dolled up overpriced water. When I managed ~150 lights lights, I switched them to a commercial salt mix. Add the price of insecticidal soap and you have an entire feed and IPM program. We ended up paying about $0.08/gallon feed and foliar even with AGT-50 fulvic as a biostimulant.
Here’s our salt mix start to finish:
(5 gallons concentrate A+B, 10ml A+B/L, 1.4 EC, 500 total gallons)
A - Chelated Micros Micros 76 g
A - Calcium Nitrate (Tetrahydrate) Ca(NO3)2.4H2O 1682 g
A - Ammonium Nitrate NH4NO3 478 g
A - AGT-50 500 ml (1ml/final gallon)
B - Magnesium Sulfate (Heptahydrate) MgSO4.7H2O 959 g
B - Potassium Sulfate K2SO4 366 g
B - Potassium Monobasic Phosphate KH2PO4 415 g
Save money compared to the hydroponics store and mix your own fertilizer!