Please do not consider using Hoagland solution for hydroponics. The concentrations are fart too big. It's much better to use more dilute solutions and replace then frequently

To make up the iron stock, take 26.1 g EDTA and dissolve in 286 ml water that has ~19 g KOH . Then dissolve 24.9 FeSO4. 7H2O in ~ 500 ml water. Slowly add the iron sulfate solution to the potassium EDTA solution and aerate this solution overnight with stirring.

Fe eddha 2.0 ppm 6% 33 g in 1000 lts 45% calcium 35% potassium 20% magnesio proporcional meq 60% NO3 10% PO4- 30% SO4-