usa water esspecially is pretty fucked up tho, Fluorosilicic acid (H2SiF6) is the most commonly used additive for water fluoridation in the United States.[41] It is an inexpensive liquid by-product of phosphate fertilizer manufacture.. mmm yummy, its also a neurotoxin , so ide reccomend somesort of reverse osmosis filter, but then also getting minerals from other spring water once a week..