Review on AQUANEAT Aquarium Air Driven Bio Corner Filter Sponge: The Ultimate Solution for Fry Shrimp Nano Fish Tanks with Airline Tubing, Air Pump Valves & Suction Cups by Kristina Perez

Great filter, plastic is good too. I lined up my carrier, kept the ceramic rings that came with this filter, and replaced the tiny stones with an underwater fluvial bio ring carrier. You can still use what comes with this filter. This gives you three types of sponges: a mesh sponge, a fine sponge, and a white sponge that promotes biofiltration. Filtering works as expected. I use it as a secondary filter in my 37 gallon tank, but you can use it as a primary filter in a 20 gallon tank with a moderate amount of bioburden. The industry shell is big enough to hold your chosen media, I filled both shells (actually overcrowded) with most of the biocarriers. See photos, hope it helps.