said by SfumatoPants :
Last night I turned it down to 150, the lower element is set to 170.
Hopefully you have anti-scald fixtures as 170 is really hot.
Time to produce 2nd/3rd degree burns at 150F = 1.5 seconds at 160F less then 1/2 second (my cheat sheet does not go above 160 degrees.
Besides scald danger standby losses will be a lot higher increasing power consumption.
Our local power utility forbids simultaneous operation and limits maximum element wattage to 5,500 watts.
/tom