Testing for adequate water mist
To test a newly built unit to see if the bubbling is
going to do the trick, simply dry off the tubs lid and
place it on the tub, turn on the air pump and let it run
for about five minutes. After around five minutes have a
look at the inside of the lid.
It should look
like the pictured lid.
Not quite soaking wet yet,
but obviously getting hit by the water droplets. Now put
the lid back on and run it for another five minutes, it
should be completely covered with those tiny water
specks or totally wetted.
If its not "completely
covered" all the way across the surface, then either
your air pump is too weak, or the bubbling device is too
small or needs to be repositioned in the tub.