A method of constructing an inner glass-lined steel tank is described. The lower edge of the top dome shell is machined wherein a smooth angulated surface is formed between an outer and an inner surface of the top dome shell to form a smooth angulated surface to eliminate abrupt transition edges. Also, couplings are machined and press-fitted into the tank wall to form smooth surfaces with the inner surface of the tank. When the porcelain enamel is sprayed inside the tank there are no sharp edges which often results in defects due to the fact that the porcelain enamel is not properly adhered thereto. Such defects eventually cause corrosion within the inner tank and greatly reduce the life expectancy thereof as well as the life expectancy of the sacrificial anode connected to the tank and extending therein.