I had my dip tube replaced recently, but seem to run out of hot water faster than before I had the defective dip tube problem. I checked the new dip tube and it seems O.K., but the length seems short for my water heater height. I have a 50 gallon water heater and the tube seems like it only goes down about 2/3 of the way into the tank. Is that normal or should the tube go down closer to the bottom? Are all dip tubes the same length regardless of heater size?