Fluval FX4 High Performance Canister Filter - up to 1000L

The Fluval FX4 High Performance Canister Filter - up to 1000L is the middle of Fluval's FX canister range, rated for aquariums up to 250 US gallons (1000 L) and built for tanks too big for a conventional canister.

Key Features

• Rated for aquariums up to 1000 L
• Smart Pump technology monitors the pump continuously and purges trapped air automatically every 12 hours
• Self-priming — fill, plug in, and the pump starts itself
• Stacked media baskets that prevent water bypassing the media
• AquaStop valves with Click-Fit connections for disconnecting without draining
• Anti-clog telescopic strainer and adjustable multi-directional output
• Complete mechanical, chemical and biological media supplied
• For use in both freshwater and saltwater aquariums
• Made by Fluval, the aquatics brand of Rolf C. Hagen, which has been building aquarium filters since 1975

Setting It Up

• The canister sits below the tank water line, in the cabinet
• Short, straight hose runs. Every bend costs flow
• A new tank has no bacteria in it. Cycling — running the filter for several weeks until it processes ammonia and nitrite to zero — has to happen before fish go in, or they sit in their own waste while the bacteria catch up
• The 12-hourly air purge is a design feature, not a fault

Maintenance

• Unplug anything electrical before putting your hands in the tank
• Close the AquaStop valves before disconnecting, then lift the canister out whole and take it to a sink or a bucket
• Rinse mechanical foam in a bucket of old tank water rather than under the tap
• Never wash biological media in tap water and never replace it all at once. Chlorine kills the bacteria living on it, and changing everything together restarts the cycle
• Service it before the flow drops noticeably. A canister that has slowed down has already been overdue for weeks
• A smear of silicone lubricant on an O-ring before reassembly makes the next service much easier and helps the seal sit properly
• Check the lid O-ring every service. A perished O-ring is the usual cause of a canister that will not prime or that weeps

Good To Know

• Fluval positions the FX4 between the 07 series and the FX6. If you are choosing between FX4 and FX6, buy on tank volume rather than on price
• Very heavy when full of water and media. Think about access before installing
• This much flow is wrong for a nano tank or for long-finned fish, however good the filter is
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see