My water heater is a 40 gallon State 510E Propane model, approximately 9 years old. For the last couple of years, Ive been having a problem getting enough hot water to fill my tub for a nice hot bath or for family members to take 2 showers in a row. This problem is intermittent. Weve turned up the heat a bit and the water is hotter but the problem persists. Ive just turned it up another notch and it is in the low end of the energy efficiency zone. When we first bought the house, this wasnt a problem. Do you think we need a new heater or is there some way to get out any built up deposit? Suggestions? What is the average life of a heater like this? Thank you…Nancy Guenther