How to Install a Fluval Filter

Three Parts:Understanding Fluvial Underwater Filter Models U1,U2,U3,U4Installing a Fluvial Power FilterInstalling a Fluval Canister Filter (FX6)

Many aquarium enthusiasts use Fluvial filters as they are innovative, easily accessible and have been a trusted brand for over three decades for small aquariums. You can buy a filter from the store suitable to the size of your aquarium and install it yourself!

Part 1
Understanding Fluvial Underwater Filter Models U1,U2,U3,U4

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  1. 1
    Read the warnings in the instructions before you attempt to install the filter. It's important to understand the dangers of the filter during use and installation to avoid electrocution.
  2. 2
    Remove all fish, decorations, and plants from your aquarium. This is for the safety and will make the process much easier. You can leave the water, however you should clean any spills on the tank or near the electrical outlet.
  3. 3
    Unpack the contents from the filter packaging. Using the diagram in the instructions, identify the parts. You may want to lay them out on the ground in groups to identify the pieces if there's multiples. It's important to have a clear understanding of the pieces before you begin.
  4. 4
    Choose a suitable designation in your aquarium to place the filter. Ensure that there is enough room above the filter to open the top cover.
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    After identifying all the parts, rinse the foam in tap water.
  6. 6
    Insert the 3 suction cups to the 3 slots on the back of the filter as directed in the diagram.
  7. 7
    Insert the output nozzle with the venturi vent into the output on the filter body. Ensure that the vent is facing upwards.
  8. 8
    If the venturi system will be used, place the venturi valve into the top of the vent.
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    The filter is ready to be fitted to the designated aquarium. Hold the filter by the sides and hold it in the desired position. When you have adequately positioned the filter, push against the filter to adhere the 3 suction cups to the wall of the aquarium.

Part 2
Installing a Fluvial Power Filter

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    Make sure all the parts are included in the package as listed in the instructions. Installation should take between 15-20 minutes.
  2. 2
    Prepare the filter inserts by rinsing them with tap water. This includes the activated carbon, poly/foam pad, bio-screen, and the c-nodes.
  3. 3
    Attach the telescopic intake tube to the "U" tube. Slide the "U" tube into place.
  4. 4
    After preparing your filter media inserts:
    • Slide the mechanical cartridge frame into the back of the filter case ensuring that the cleaning indicator is to the right.
    • Slide the chemical basket and the trickle chamber into the filter case.
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    The power filter must be level to run optimally.
    • Insert the leveler into the bottom of the filter case.
    • Mount the power filter onto the back of the aquarium.
    • Adjust the leveler by turning it to the required setting to ensure that the filter is sitting perfectly vertical.
  6. 6
    With the filter cover removed fill the power filter case with water. Replace the cover.
  7. 7
    Adjust the water flow to it's minimum position for the initial start up and priming of the filter.
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    Plug the electrical cord into a proper electrical outlet. Allow a few seconds for the priming as the air is being removed from the "U" tube.
  9. 9
    Adjust the water flow setting to the desired position when the filter has been primed. Clean the media every 2 weeks. Maintain a water level of no more than 6 cm ( 2.25 in) below the aquarium rim.

Part 3
Installing a Fluval Canister Filter (FX6)

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    Read and follow all safety instructions.
    • Read the remaining instructions.
    • Unpack and identify all of the parts.
  2. 2
    Prepare the aquarium. Decide where the filter will be placed. For the best results, fill the aquarium with the maximum level possible.
    • The filter lid must be located at least 7.8 in. (20 cm.) below the aquarium's water level, but never more than 4.9 ft. (150 cm.)
    • For the best results the filter should be directly underneath the aquarium.
  3. 3
    Place the 2 rim connectors over the back, top edge of the aquarium.
    • Place one where the intake tube will be placed.
    • Place the other where the output nozzle will be positioned.
    • The rubber rings on the connectors are designed to help them adhere to the glass sufficiently. If the aquarium walls are less than 5/8 in. (1.58 cm.), replace the rubber rings with the 4 smaller suction cups that are provided.
  4. 4
    Prepare the intake connections.
    • Connect the hosing to one of the two valves.
    • Loosen one of the metal clamps and slide it onto one end of the hosing ( the rubber part ).
    • Push the end of the hosing onto the valve. Push it as far as it will fit.
    • Position the metal clamp over the rubber connector. Tighten.
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    Measure and cut the hosing.
    • You will need a length that reaches comfortably to the canister.
    • The hose should follow a straight path with no loops or slack.
    • Place the valve end of the hosing at the approximate spot where it will be positioned onto the filter lid ( once the filter is installed ).
    • Stretch the hosing so that it rests over the "output" rim bracket.
    • Using a utility knife, cut the hosing at least 6 in. (15 cm.) beyond the aquarium rim. do not cut it too short!
  6. 6
    Push the cut end into the "intake" hosing into the rubber connector on the intake tube. Insert it at least one inch (2.5 cm.) without twisting it.
  7. 7
    Place the intake strainer into the tank. Ensure it is at least 3 in. (7.5 cm.) from the bottom. Adjust the intake tube for the best extension for the desired aquarium.When the intake strainer is positioned, lock it in place by pressing the suction cups against the glass.
    • Fasten the intake strainer's hosing onto the rim connector using the 3 rim connector clips.
  8. 8
    Prepare the filter. Loosen and separate the 8 lid fasteners. Remove the filter lid and set it aside. Using the red T-handles, lift the 3 media baskets from the filter canister.
    • Rinse the baskets and filter media under running tap water to remove dust. Place in the media baskets.
    • Place the rinsed and filled media baskets back into the canister. Ensure it is placed the same way it was removed unless you are changing to a different filtration plan other than the one recommended.
    • Stack the baskets, aligning them so that the shapes match. Reinsert the T-handles into their vertical slots.
    • Replace the baskets in the filter canister. the foam in the upper basket should be about even with the top edge of the canister. The output tube will be protruding slightly.
    • Move the filter canister into it's final position.
    • Ensure that the purge valve is vertical (closed).
    • Pour at least 2 gallons, (8 liters) of water into the filter canister.
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    • Place the filter lid back on the canister.
    • Check to see that the filter lid seal ring is present and installed properly. Press the lid down until the output tube is firmly seated in the OUT connection on the filter lid.
    • If the inlet tube attached to the canister lid has slipped out of it's seat, re-insert it under the IN connection of the lid.
    • Replace and hand tighten the 8 lid fasteners. The lid is properly closed when it is in direct contact with the canister.
  9. 9
    Make sure the aquarium has been filled with enough water.
    • Grasp the intake valve (which is at the end of the hosing attached to the intake tube); slide it onto the IN connection on the filter lid. Press until it clicks into place.
    • Grasp the output valve ( which is at the end of the hosing attached to the output nozzle); slide it onto the OUT connection on the filter lid. Press until it clicks into place.
    • Make sure both valves are locked into place and that the valve levers are in the open (vertical) position before proceeding.
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    Plug the filter into an electrical outlet.
    • The automatic priming sequence will begin.
    • The pump will run for one minute to fill the filter canister with water.
    • The pump will stop for two minutes to evacuate air from the filter canister.
    • The pump will restart. It will remain running until it is unplugged.
    • This sequence will repeat itself when plugged in again.


  • Be sure to read and reread the instructions. Do not get rid of the instructions. Keep your receipt.


  • For the underwater filters U1-U4, note that in order to have the airflow /venturi work properly, it must remain above water. Keep this in mind when putting the filter into its final position. Turning the valve located on the top of the venturi valve will regulate the quantity of air produced.
  • For the underwater filters U1-U4, be sure the line cord is correctly positioned in the slots on the back side of the filter body. Ensure the top outlet is at a minimum of 1 cm below the aquarium’s water surface and if you will need the venturi valve, ensure that it is protruding out of the water.
  • For the power filters, an additional extension tube can be purchased separately for deep aquariums.
  • Do not operate the filters without water.
  • To prevent blockage, all filter media must be placed in the filter baskets.

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Categories: Aquariums