Filter Cleaning

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John's Technical Tip: Fluval Cleaning

The middle of the school year is a great time to check and clean your filter media.  Please check your filter's manual for detailed instructions.

For the Fluval 405 filters, you must first raise the shut off valve (gray/black pedal) and make sure that the output hose is not circulating water, THEN unplug the filter and remove the top.  

The foam media should be removed and thoroughly rinsed.  The ceramic and charcoal media should remain submerged and not disrupted, these media support the living bacteria responsible for stabilizing your tanks nitrogen cycle.

If you notice living or dead trout in your filter or in the media remove them immediately, live trout can be placed into the tank.  Extra precautions must be made to prevent trout from being suctioned into the filter system.  The filter intake must be covered with a filter foam or mesh material on all sides, top and bottom.  This cover will likely accumulate waste material and will need to be removed and cleaned each week.  Make sure to raise the shut off valve before removing the filter intake cover to prevent fish from being taken in during a cleaning. 

John Fischer recommends using the AquaClear 110 filter foam block (found at most pet stores) to prevent young trout from being suctioned into the Fluval 405 filter intake. The foam block is made of a porous spongy material.  To fit the foam on the filter intake, cut the foam block in half and make crossing slits on the top with a small pair of scissors, when you squeeze the block you should be able to see the opening where the filter intake fits. Be sure NOT to cut all the way through to the bottom (see pictures below). 


Treat all of the tank water with water conditioners (such as Amquel and Novaqua) to remove any chlorines, chloramines, ammonia or metals that may have contaminated the filter media during cleaning.  Also remember to clean your hands of lotions, soaps and oils prior to handling filter and aquarium equipment.

To start the Fluval 405 filter back again, replace all media and covers, lower the shut off valve (gray/black pedals) to open circulation.  Prime the 405 Fluval Canister filter by pumping (raise and lower) the silver “start” knob.  Keep pumping the water through until the chambers are filled with water and air has been expelled, and then plug in the filter.  You should see water come out of the output hose.  If the water is not circulating, and the filter is making noise, try priming or unplug and check to make sure the system is set up properly.

Detailed instructions for the Fluval 405 are available at online (


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