JBL CristalProfi i60 GreenLine

JBL CristalProfi i60 GreenLine is an internal filter for aquariums of 40 to 80 litres, built as a corner unit so it tucks into the back of a tank rather than taking up a wall of it. It arrives with its filter media already in, so it is a case of fitting it, plugging it in and letting it run.

Key Features

• For 40 to 80 litre tanks: JBL's figure, and the first thing to get right.
• Corner shape: a filter shaped to the corner takes up far less visible space than a flat-backed one.
• Mechanical and biological in one: the foam strains the water and houses the bacteria that process ammonia and nitrite.
• Comes with its media: nothing extra to buy before you can run it.
• Rotatable outlet pipe: aim the return where you want the circulation rather than where the filter happens to sit.
• Modular: the cartridges come out and swap individually, which is what makes servicing quick.

Fitting An Internal Filter

• Mount it fully submerged, with the outlet at or just below the surface so it breaks the water a little. Surface movement is how oxygen actually gets in.
• Aim the outlet along the length of the tank rather than across it, so you get circulation instead of a dead end.
• Leave room to lift it out. A filter wedged behind rockwork is a filter that never gets serviced.
• Never run it out of water, even for a moment. These pumps are water-cooled.
• Rinse the foam in tank water at each service and squeeze it gently rather than wringing it out.

Good To Know

• A new filter has no bacteria in it. Stock slowly over the first weeks, feed lightly, and test ammonia and nitrite until both read zero. A filter becomes a filter over about a month.
• Rinse filter media in tank water, never under the tap. Chlorine kills the bacteria that do the biological work, and that is most of what a mature filter is worth.
• Service before the flow drops noticeably. By the time you can see a filter struggling it has already stopped doing part of its job.
• Switch the filter off at the mains before opening it or putting a hand in the tank, and fit the cable so water cannot run down it to the socket.
• An internal filter takes up space inside the tank and is visible. That is the trade for not needing a cabinet or hose runs.
• Suction cups perish and lose their grip over time. Check them at each service, because a filter that drops onto the substrate stirs up everything it has collected.