Should I replace water heater thermostat

[JCA1]

I think it's a mineral deposit problem. Properly flush the tank and try it then, if no improvement replace the upper t-stat first and try it.

[LazyPup]

I am not in the habit of changing out any component unless I am certain that it is defective..but if you have your heart set on replacing the t/stats have at it. You can't hurt anything in the process and you will only be out about $30.