Thanks for the reply,
The tank is 80 gal. with only one heating element near the top. The solar collectors on the roof are filled with antifreeze which is pumped down to a heat exchange tube which heats the water. The solar hot water goes in the bottom of the tank and the hot water in the tank rises and mixes with the electric heated water. The hot water to the house comes out the top. So we heat 40 gal with electricity and heat 40 with the sun. The cold water comes into the top. I hope this helps.