Do you have a Window in your MES?
If so does it often get covered with condensation on the inside?
That's because it is insulated so good that there is already too much moisture in an MES, without adding any to it.
I haven't put any liquid in my water pan in 8 years, and never had anything come out dry because of it.
The window fills with condensation & runs down the glass. I can wipe it dry, and it's filled up in less than a minute again.
I forgot all the bad things about putting water in an MES water pan, because just knowing it doesn't do anything good is enough reason for me.
Bear