Homemade cal mag from eggshells. I use 8mil per gallon and its organic and beats any store bought stuff. I used a hand torch to burn half the eggshells and rite after add the apple cider vinegar to react til the next day and then i strained and use for my plants. 8 mils per gallon and there you go . For more of a how make your own check out Korean natural farming growing techniques and keep it natural and organic.