I do not add any salt, it has no provision for batteries, a small washable filter keeps stuff from getting into the base tank water. On real hot and dry days I can feel a very slight mist getting into the air when I place my hand about 12 inches from the outlet. I see and feel no moisture on the floor from it.
On first use, my kitchen table got wet after about 15 minutes of running. I noticed on top of the base was a small drain/breather hole that was not allowing any water to get back into the base. I took an 11/64 drill bit and drilled the small hole a bit larger and at a slight angle. The water drained instantly and has not got wet since.
As to noise, the fan has a low slight hum that can be heard across the bedroom. I can also hear the fan noise too that sounds like a frying pan frying bacon when a few feet away. I fell asleep quickly and it does not bother me. It may bother those that need a quiet fan that mine is not.
There is no shut-off switch on my model. It says to make sure it is not run dry. That could be a problem to some.
Exactly what I need to add cool moisture into the air and so easy to clean and add water too.