I bought zinc pills recently in the hopes of using them as yeast nutrient. I ground them up in a coffee grinder to make a fine powder. Now I'm trying to determine how to actually add it. On page 75 of White/Zainasheff's "Yeast" book, they suggest adding .2 to .3mg/L near the end of the boil for enough nurtrient in the fermentor. Therefore, in a 6 gallon boil, roughly 23 L, I would need 7 mg of zinc, or .000246918 ounces. How does one measure out such a miniscule amount without a digital scientific scale? Thought I read on some website where someone suggested a specific dilution of zinc powder in water, where a few tablespoons of the solution equated to the right amount of zinc. Also, White and Zainasheff reference zinc chloride or zinc sulfate. My pill jar lists zinc gluconate as the main ingredient, with several other filler ingredients such as cellulose, dicalcium phosphate, stearic acid, croscarmellose sodium, glycol, and magnesium stearate. Will this zinc be appropriate?