it's likely the bottom element, yes.
I didn't get a chance to check out the results of the temperature change as I had to leave after doing the adjustment. I will go back with a thermometer and see what the water temp is. Then I will run the water for a long time and see how long the hot water lasts.did turning up the bottom thermostat help?
Thanks for your response. I rather doubted the temp setting was the problem too. The two thermostats look a little different and only the top one has a reset button which had not popped-out but which I pressed anyhow (with no movement). I have no idea how much the thermostats cost but it may make sense to just replace both if I can determine that they are the culprits. Your info will help me figure that out. Cheers!It is likely that both thermostats have red reset buttons. Make sure these have not tripped on the thermostats. If so reset and see what happens. I doubt it is the temperature setting since you used this for years without complaint. Most likely a thermostat problem and likely the lower thermostat.
Both thermostats do not heat at the same time so when the top reaches it's setting it closes a circuit to the lower thermostat. Check voltage at the lower heating element across both hot wires when it calls for heat. Should have 240 volts. If not the upper thermostat may be faulty or it could be the lower one. Depends on where voltage is present and where it isn't. No voltage on the wires to the lower thermostat at the upper thermostat terminals would lend to a faulty upper thermostat. Voltage at the connection to the lower thermostat but no voltage at the lower heating element, then problem with the lower thermostat.