What are these called???

[Maj0rFiSh]

What are those filters called that have a circular sponge half in the water half out?

They clean the muck floating on top am i right, look like these...

http://www.aquatics-warehouse.co.uk/acatalog/hydorwetdry.jpg

What are they called!?!

 

[aquanewb]

I believe it is called a bio wheel, unless I am mistaken.

 

[SnakeIce]

part of the link states that it is wet dry, that wheel must rotate in the flow of the filter and provide air water exchange for the nitrification bacteria.

it might break up any surface junk but thats not what it was designed for.

 

[Jason01]

The link here describes what it does pretty good!
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=11366&N=2004+22779

For all you non-clickers out there:

These hang-on filters improve your aquarium's biological filtration and provide alternating water current - without additional equipment. Hydor's BIOFLO sponge draws in surface oxygen and beneficial bacteria, while the rotating deflector output creates a natural wave effect

Actually, they did a pretty bad job describing it. I have an idea of what it does, but not entirely. The described it kinda like a Saturn V rocket. I know what it does, but not how/why it does it! :laugh:

 

[Timmain42]

I run one of the larger Bioflos as the sole filter on a 55G FW planted. Works INCREDIBLY well. If you're short on filter options due to lack of space surrounding the tank, this works quite well. However, I would not recommend a single Bioflo for any water volumes larger than 35 gallons.