The Fluval 07 Series Canister Filter is Fluval's 07 Series external canister filter, sold in four sizes from the 107 up to the 407, which sits in the cabinet below the tank and hides all the hardware out of sight.

Key Features

• An external canister: the filter lives under the tank and only two hoses and an intake and outlet are visible in the water. That is the main reason people move up to one
• Four sizes — 107, 207, 307 and 407 — each rated for a larger tank than the last
• eTEC construction, Fluval's name for the motor and impeller design that gives the flow while keeping power draw and noise down
• Stacked media baskets that can be filled as you choose, so mechanical, chemical and biological stages go in the order that suits your tank
• AquaStop valves let the hoses be shut off and disconnected without draining anything
• Far more media volume than any hang-on filter, which is what makes a canister the right answer for a heavily stocked or large tank
• 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

Choosing A Size

• Pick the size by tank volume and by stocking. A lightly planted 200 L tank and a 200 L cichlid tank are not the same job
• Going one size up is the usual advice. An oversized canister run gently outlasts a small one run flat out
• Leave room in the cabinet — a canister needs to sit below the water line and needs clearance to lift the lid off

Setting It Up

• Fill the canister with water before the first start. Canisters self-prime but they do not like being started bone dry
• Get the hose runs as short and straight as you can. 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
• Move media across from your old filter if you have one. That is how you keep the bacteria and skip the cycle

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

• A canister holds several litres of tank water. Work over a towel and have a bucket ready, because the first service of a new filter always spills something
• The 107 suits tanks around 130 L, the 407 around 500 L, but use Fluval's rating on the box rather than a rule of thumb
• Canisters are quiet when level, full of water and free of trapped air. Tipping the unit gently once running clears most rattles
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see