Post a picture of the plant, preferably under white light, not under HPS or Purple LED.
If you have a mix of calcium, magnesium, sulfur, and other micro nute deficiencies, then maybe it will help, but you don't give how much of each, how the eggshells would be dissolved, or how much water... Nor do you give exact enough symptoms to diagnose if you even have a deficiency vs PH vs over-watering issue. No way to answer without any info.
Show us the plant.
Tell us about:
Soil (brand, source/recipe if diy mix, whatever info you can give.)
How often are you watering? How do you know when to water?
Are you using nutrients in the water? What nutrients? How many PPM or How much per gallon/liter. What PH?
Lights: size, type, height?
If you provide most or all of that info we should be able to diagnose the issue and find the best course of action.
