I found this item when searching for something else but really want one now. This is in German and I can't find the right terms to search with to find a similar item in English.
http://www.ebay.com/itm/Turbo-Luftheber-Airlift-20mm-63mm-Pumpe-Wasserumwalzung-Mattenfilter-Filter-/281153286501?pt=de_haus_garten_tierbedarf_fische&var=&hash=item41760ab165
http://www.ebay.com/itm/Turbo-Luftheber-Airlift-20mm-63mm-Pumpe-Wasserumwalzung-Mattenfilter-Filter-/281153286501?pt=de_haus_garten_tierbedarf_fische&var=&hash=item41760ab165