I test my horses' hay and then supplement micro and macro minerals to the analysis. In California feed stores, you can't buy stuff this way, individually. I have ordered small amounts (3-5# at a time) of certain minerals from Horsetech, but it is expensive. I am on horse forums where people in other parts of the country say they just get a 50# sack of calcium carbonate from their feed store for $15 or so. Well, in CA, you ask the feed store and they haven't got a clue what you are talking about or how to help you.
I found one company who does all grades of limestone but only by the truckload! I'm just wondering if anyone out there might know how to find distributors in California who deal in bulk sacked minerals. I also use a lot of poly zinc and poly copper. Anyone out there know where to direct me?