I have located a 275 gallon tank that had iodine in it. The guy says he has sold these tanks to other people for the use of sap storage. When I asked him if they were food grade he said they could be used for potable water but stayed away from saying they were actually food grade. He also said the plastic had a brownish tint from the iodine. He says he has other tanks that had vanilla extract in them but I wouldnt want those and the iodine were the way to go for sap storage. Im thinking this tank isnt the right way to go, but Im not sure. Any advice? Im pretty sure he was looking for the sale but who wouldn't.