Looks like this will work very well. It's as cold and dry a morning as it gets in N. FL. I had the tank open with no water bowl when I was working on my top. Humidity dropped to 20%. I put the finished top on with a bowl of water inside and completely closed it up. Humidity rose to 55% in 2-hours and I opened the holes. It appears that it is stable at 55% with the holes open. I can close it up again if I need it to go higher.