Actually I use them as filters/water movement in a lot of my pleco tanks and none of them have failed. I refitted one of these.
http://www.drsfostersmith.com/Produc...&N=2004+113424 by removing the fine filter pad and tossed it in the trash. On the inside of this filter tube is a smaller diameter plastic screen tube. Wet dry filters sometimes use a tube shaped foam filter for a pre filter. I found this to fit perfectly over this internal screen tube and the outer plastic clamps perfectly around this foam. I then filled the inside of the screen with bio rings. The foam is large pored and works great for this application.