When I decided that I wanted to have an aquarium so that I could keep fish, the aquarium that I purchased was just the first step to getting started.
If I was going to keep my fish healthy, I also needed to have a reliable and a top of the range filtration system.
After much research, I selected the Fluval FX6 due to the good reviews that I had read about it. As it is able pump out 3500 litres per hour, with such a high output it is able to keep a very large aquarium spotlessly clean.
An added plus was that it is noted for its quietness. Perfect if your aquarium is kept indoors as mine is.
However, there will be occasions when you may find that your Fluval is making more noise than normal. The filter can sometimes start to vibrate and pulsate, and also make a knocking sound.
Additionally, there may be a bubbling sound coming from the aquarium itself. This generally happens to your Fluval FX6 when the impeller on the filter canister needs to be replaced. But don’t worry, this is an easy problem to fix.
I also made a video about this topic and you can watch it below. On my video, I demonstrated how to solve this problem. First, I remove the impeller and clean it. If this fix doesn’t work you’ll need to replace the old impeller with a new one.
How to Fix Fluval FX6 Pulsing, Vibrating and Knocking Sound
What you will need to do is to remove the pump unit from the filter canister.
Simply carefully unscrew it from the front of the canister, and first of all ensure that where the impeller fits in to the canister that it is free of any debris as this could simply be the problem.
Next remove the old impeller from the pump unit – it just needs to be pulled out. You can compare you’re the old impeller with the new impeller that you have purchased to see if there is actually any damage to the old impeller.
But do make sure to buy a legitimate Fluval impeller for your FX5/6 as while pirate parts may be cheaper, they will only cause more problems in the future.
However, sometimes the old impeller may just need cleaning rather than replacing in order to stop the vibrating and knocking sounds that you may be encountering.
Therefore, having inspected the current impeller for any signs of damage, if non are visible, before you change the impeller give the current impeller a good clean to see if this may rectify the problem.
It would be such a waste of money putting in a new impeller if the old impeller only needed to be cleaned.
If the impeller does actually need replacing, firstly fit the rubber seal securely into its position to ensure that there will be no air leaks.
Related: How to Solve Fluval FX6 Filter Trapped Air
Next, insert the new impeller into place. Make sure that you have clicked it into place properly otherwise it will not work correctly and cause you more problems.
You can check this by making sure that the impeller will spin correctly by spinning it with your hand.
Once you are sure that you have fitted the rubber seal and your new impeller correctly, you can reattach the pump unit to the filter canister.
Again, ensure to fit it properly back on, and make sure to screw it back on correctly so that no leaks are encountered.
Now you should find that your Fluval FX6 is once again working to its full capacity, and as soundlessly as expected – no more pulsing, vibrating and knocking sounds.
