The Fluval FX6 High Performance Canister Filter - up to 1500L is the largest canister filter Fluval makes, rated for aquariums up to 400 US gallons (1500 L) — a filter for monster tanks, turtle setups and heavily stocked cichlid systems.

Key Features

• Rated for aquariums up to 1500 L
• Smart Pump technology monitors performance and evacuates trapped air automatically every 12 hours
• Self-priming: fill it, plug it in, and it starts itself
• Very large stacked media baskets, designed so no water bypasses the media
• AquaStop valves with Click-Fit connections
• Anti-clog telescopic strainer and fully adjustable output nozzles
• Complete 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

• Must sit below the tank water line
• Keep hose runs short and straight, and make sure the cabinet can take the weight
• 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 periodic air purge is normal operation

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

• The FX6 is a lot of filter. On a tank under about 400 L it is overkill and the current will be a problem for the fish before the filtration is a benefit
• Extremely heavy in use. Work out how you will service it before you buy it, not on the day
• Two smaller filters on a big tank is a genuinely reasonable alternative — if one fails you still have filtration
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see