The Fluval C2, C3 & C4 Power Filter Seal O-Ring Gasket is the genuine seal O-ring gasket for Fluval's C-Series clip-on power filters, covering the C2, C3 and C4.

Key Features

• Fits the Fluval C2, C3 and C4 power filters
• A perished gasket lets water bypass the media, which quietly ruins the filtration without any obvious symptom
• Rubber hardens over a few years in warm water. This is a routine replacement, not a repair
• Made by Fluval, the aquatics brand of Rolf C. Hagen, which has been building aquarium filters since 1975

Fitting It

• Unplug anything electrical before putting your hands in the tank
• Disconnect the hoses and take the unit to a sink rather than working over the tank
• Check the old part against the new one before fitting. If they differ, stop and check the model number
• A smear of silicone lubricant on an O-ring before reassembly makes the next service much easier and helps the seal sit properly
• Prime the filter and watch the first few minutes of running for leaks before you walk away

Good To Know

• A smear of silicone lubricant on an O-ring before reassembly makes the next service much easier and helps the seal sit properly
• Seat it fully before reassembling — a pinched gasket is worse than a worn one
• If the filter is bypassing media, check this gasket before blaming the pump
• A genuine Fluval spare part. Check the model number against your unit before ordering — Fluval part numbers look alike and do not cross over between series
• Fluval sells these individually so a filter can be repaired rather than replaced, which is usually the cheaper and greener option
• Keeping a spare impeller and O-ring in the cupboard saves a tank when something fails on a weekend