This is a good way to add O2 to your aquarium without all of the issues concerning splashing. It's a bit large for a nano tank/shallow tank, but would do well in anything larger than a 10g.
I'm using for aeration at night for growing bacteria in my ADA planted tank! No water splash, comfortable air sound, beautiful glass! It's good match with ADA products. One of the best product in my aqua life.
I purchased a spell with the intent of using it as a passive CO2 container. It worked out well the only thing I had to do was use some silicone and fill the tiny pinhole at the top. This is a perfect option for a small tank and it looks beautiful I highly recommend it!