Review on 🐟 Fluval 110V Magnetic Impeller with Straight Fan Blades (404, 405): Enhanced Water Circulation for Aquariums by Barb Cook

Perfect for my 404. I knew my impeller was failing as it got loud and stopped working. However, I didn't notice it until it went bad (it twisted in half and damaged the plastic). In case this happens to you and you don't know what to do (I can't imagine you would have a filter this size unless you have aquarium knowledge) connect the air pump and air stone. This keeps the oxygen in your water, although your nitrogen will continue to build up, until you turn the filter back on. However, this will save your fish for a while (I had this for a few days).