I would not recommend turning the email alarm "OFF." That would stop the notification of all alarms. The reason why a "Set Off" alarm occurs is because something is going to an alarm state (like your optical sensor on your FMM or your temperature) and by the time the alarm actually sends that sensor is no longer in an alarm state. It is best to find out what the sensor is near an alarm state and correct that issue (maybe move the sensor up about a quarter inch or adjust your temperature to alarm .1 to .2 degrees higher/lower).
Finally, one option is to also add a "DEFER" statement to your email alarm out. A defer statement will prevent an outlet from going to an on(or off) state for a specified period of time. For example, if you click on the gear on your email alarm outlet and after all the other lines of programming add:
Defer 0:30 Then ON
It will say, "Only go to an 'on' state if that 'on' state is true for more than 30 seconds". So, in the example of your optical sensor the water level would need to be above the sensor for 30 seconds before the alarm would be triggered. Please also be aware the defer statement will apply to ALL conditions of the email alarm outlet. So all alarms would be delayed from triggered for about 30 seconds or so.