Problems with the Fluval 404

If you love fish and have a 100-gallon or larger aquarium, the aquarium most likely has a canister filter. Hagen Fluval 404 aquarium canister filters are considered among the best on the market for regular consumers. As with anything that has moving parts, this filter needs maintenance and repair on occasion. Everything on the Fluval 404 series filters that encounters a problem is fixable and replaceable, except for the interior components of the main drive motor, which is sealed for safety reasons.

  1. Dirty Filter

    • A dirty filter within a Fluval 404 will greatly reduce its efficiency and slow the aquarium's water flow. A regular schedule for cleaning the filter media must be maintained to protect fish and to extend the filter's life. Cleaning the filter once each week is optimal. Hagen provides online, step-by-step instructions about how to maintain a Fluval 404 filter, and they are linked in the Resources section.

    Clogged Primer

    • The Fluval 404 has a primer pump that you have to press after you clean the filter. This pump releases air so that the filtration system operates properly. Because this primer is located before the filter media in the Fluval 404, it can become clogged, causing the filter to not work correctly. The primer needs to be cleaned and reassembled.

    Blown Motor

    • If you don't hear a sound, including rattling, from the motor when the Fluval 404 is plugged in, it may have a blown motor. This happens when the system is not primed and/or not enough water is in the filter. The motor needs water at the impeller in order to work and cool down. You can try to correct the problem by filling the filter with water, or you can obtain replacement parts.