Bests & Worsts Reviews from Amazon

I was really excited to get these, I ordered 2. They had pretty good reviews compared to some of the more expensive ones and I am just getting into aromatherapy and on a tight budget. Anyway, following the directions I filled them both up with water to the fill line and added a few drops of essential oils to help with a cold/breathing. Plugged em in and didn't see anything. One of them was expelling a very, very faint mist and the other I didn't see or smell anything. I let them both run for several hours just in case. The first one with the faint mist did improve after the water level went down about a third, the other one never did seem to improve so I unplugged it. Was worried there was a problem with them both so contacted returns at Amazon to get info/label for returning them both. The next morning I thought I would give it one more try. The first one seems to be working pretty good. The second one, I started with just about 1 1/2 inches of water on the bottom and it started misting. I added the essential oils and then more water to about 3/4 full and it continued to make the mist. I guess probably best not to fill them to the fill line like in the directions. Since they both seem to be working I guess I will keep them and see how it goes, stay tuned. Okay, next day having problems with both misters so have decided to send them back, its so frustrating, but I don't want to keep messing around with them and then have missed the date to return them. Better safe than sorry.