If you are on a budget and are related to Red Green or McGuiver, a great, most times free mash/sparge water heater are used 40 gal electric hot water heaters - cut them in half and voila - a great heater (have to bend the element down near the bottom) with adjustable thermostat with the bottom half, chop the element off, flip the top upside down with a collapsible salad drainer for false bottom and you have ur sparge vessel. They are glass lined so no contact with steel tank. Have not tried it but am sure bottom would make a great boil pot as well as convex shape in bottom and thusly way more heating surface area as well as plain steel is much more heat conductive than stainless.