waterdrop
Enthusiastic "Re-Beginner"
Are you sure it's not air noise? Whenever you perform maintenance on an EC filter the media will of course get air bubbles all through it and those bubbles can collect at the top of the filter box and create noise as they interact with the impeller blades.
One trick to seeing if this is the case is to carefully and gently lift your filter (take care that you don't knock off tubes, etc) and give it a small stiff vibrational shake while tilting it very slightly at different angles slightly off of straight-up. If you have air this should cause some of the bubbles to dislodge and go shooting out the output tube. You should hear a swishing noise and possibly see a sputter at the spraybar or outlet.
Of course if it's pump noise then it may be caused by a worn impeller assembly which needs to be cleaned or replaced. Or it could just be the noise that a Fluval makes. There are plenty of variations within manufacturer but many consider the Eheim to be the rolls-royce of filter systems, in terms of lack of noise.
~~waterdrop~~
One trick to seeing if this is the case is to carefully and gently lift your filter (take care that you don't knock off tubes, etc) and give it a small stiff vibrational shake while tilting it very slightly at different angles slightly off of straight-up. If you have air this should cause some of the bubbles to dislodge and go shooting out the output tube. You should hear a swishing noise and possibly see a sputter at the spraybar or outlet.
Of course if it's pump noise then it may be caused by a worn impeller assembly which needs to be cleaned or replaced. Or it could just be the noise that a Fluval makes. There are plenty of variations within manufacturer but many consider the Eheim to be the rolls-royce of filter systems, in terms of lack of noise.
~~waterdrop~~