I am a retired electronic engineer and no scientist. I am considering the use of a saturated solution of sodium chlorate as a thermal store. My problems are: 1/ I have no idea of the quantities involved in terms of heat/gram of crystals. My intention is to maintain a supply of hot water for a house or boat using solar heating. 2/ I don't know of any corrosive effects of such a solution on the container. Would a stainless steel vacuum-insulated tank work?