Instruct: Classify Amazon reviews into positive or negative sentiment
Query: not easy to fill

The humidifier works well. It takes a few days of adjusting both dials to get the humidity set to the desired level. At first it will go through the water like crazy, but once you get it set right, it uses less. My only complaint and the reason I returned this is the tank is awkward to fill. The cap is on the underside, so after you fill it, it needs to be turned upside down to screw the cap on. The problem with that is the top of the tank is curved, so you need to make sure to hold it otherwise it will fall and spill. It is also heavy since it holds so much. I prefer theVicks UV 99.999% Germ Free Humidifier. It does cost more, but I think it is worth it. It has two tanks that hold a comparable amount of water in total and they are flat on the top so they can be set down when filling.