How much energy is required to raise the temperature of 1000 gallons of water  by 25OC?

Energy is not a physical unit. It is a philosophical concept and an accounting technique used to analyze mechanical and chemical exchanges. In nuclear physics it is defined as a wavelength of light, in biology it is a synonym for metabolism, and in public utilities they say energy when they mean connectivity. Anybody who uses the word in any other context either does not know what he is talking about, or is peddling something you don't need.

What you are talking about is heat. The amount of heat to raise the temperature of water depends on the temperature of the water. Water boils at 100C, but if it is confined then pressure increases without boiling and your container is in danger of rupturing. So the amount of heat is not the major concern in this project. You need to take some time and learn your subject so you don't injure yourself.