Penn-Plax Small World Aquarium Air Pump and Filter Kit

The manufacturer recommends changing the filter cartridge every 4 weeks or so. I didn't see this in the description, if it is there. Had I known, I might not have bought it. That said, for those who prefer to not waste money on such hooks there is a fix. I heated 2 cups of water in the microwave for two minutes. Then I put one end of the cartridge in the water to soften the glue holding the back panel of the cartridge. I then separated the two pieces of the cartridge cage as much as possible. When that was done I put the other end in the hot water and did the same from there. I then inserted some filter pad that I had laying around in the cartridge cage. I didn't replace the back of the cartridge cage. I stuck the main part of the cage with the foam back on the rest of the main unit and used a zip tie to hold it on. I cut the zip tie so that there was enough to hold on to. That makes it possible to open the zip tie the next time I need to clean or change the filter material. If you find that you need carbon or other materials you can buy filter pad containing such and cut it to size. You could also use filter foam or filter floss instead of filter padding. Its basic design suitable for a small tank. It is a shame that Penn Plax chose to try to hook people with cartridges that aren't even carried in the store. They did have the decency to include an air valve to adjust the airflow. They did not include a back flow valve so if you don't have one, get one.

Very loud, noisy and even falls off the table from its vibration whilst it pumps air into water