AZOO 2 Oxygen Plus Bio-Filter

[Cholly]

Cheap and effective. I added it to my then cycling 55 when it had cloudy water, which I had assumed was bacterial bloom. Either it wasn't a bloom, just suspended particulate, or this filter is unbelievable, because the water was crystal clear in under 2 hours. I would highly recommend it as a polishing filter if nothing else.
The lift tube is too small to allow powerhead usage, but it appears not to need it. In my case, I'm using it as a supplementary filter, because it's rated for 120 liters(Approx. 32 gallons), but I'm thinking about getting a second one and doing away with the HOB entirely. It would make sealing the tank much simpler, and considering that it's intended to be a bicher tank, that would be a big plus. I wouldn't have to worry about sand in the impeller, either.
The only thing I really don't like is how loosely it anchors into the supplied suction cups. I only had to remount it once, but it was still annoying.
One of my big barks about sponge filters has been aesthetic, they're usually ugly. Great for fry, but not for a display tank. Not so with this one, nor is it overly bulky. Overall, I'd give it four out of five stars so far, time will tell more.