well the end of the tube that is in the tank, can you feel air blowing out of it? if you don't then somethings wrong.

How long have you had it running? it could take a day or to to raise the humidity any.

the whole concept is that the air in the bottle above the water is saturated with moisture, and by pumping air into the water you are forcing the saturated air out and through the tube into the tank. this moisture filled air will help raise up the over all humidity.

i use mine all winter when it's driest here, and it kept the humidity up to 57%. i took it out this summer because it was pushing humidity up to 75%.

hope this helps.