Help me with math. I tried to follow the calculations but I come up with a total ppm added of 0.07 and I thought an Fe of 0.2 to 0.5 ppm was desired.

Fe chelate 10% 5 g into 1 liter = 0.5g/l = 500mg/l = 500ppm = 0.5mg/ml
Adding 45ml/wk = 22.5mg/wk
90 gallon = 340 liters
and
22.5mg/340l = 0.07mg/l or 0.07 ppm

Are my calculations correct or where did I go wrong?

Craig