You are growing very nutrient demanding plants. Lack of micronutrients like iron and others could be the problem. Miracle grow doesn't have all the micros if any last time I checked.
Adding compost adds micronutrients, they also make liquid additive. (Fe, B, Cu, Mn, Zn)
Calcium and Mangnesium are added in same amounts as N,P, or K. (Ca, Mg) are secondary Macronutrients.
I made a similar mistake to the point where I wore out my garden plot and so am doing a soiless garden this year.