JBL ProCristal i30

JBL ProCristal i30 is a small internal filter for tanks of 10 to 40 litres, the size most people start with or keep a betta or a shrimp colony in. The pump adjusts up to 200 litres an hour, and the intake surface is fine enough that small fish and shrimp do not get drawn into it.

Key Features

• For 10 to 40 litre tanks: JBL's figure, which covers nano tanks and small species setups.
• Adjustable up to 200 litres an hour: turn it down for a betta or a shrimp tank, up for a tank with more in it. An adjustable pump is the thing most small filters lack.
• Fine intake surface: JBL's own point: the fine-pored surface stops small fish and shrimp being sucked in.
• Suction cups, any side: sticks where you want it, which matters in a tank with little room.
• Oxygenates as well as filters: the return breaks the surface, and surface movement is what gets oxygen into water.
• TUV tested: JBL's own note on the pack.

Fitting It In A Small Tank

• Mount it fully submerged and set the outlet so it just ripples the surface rather than churning it.
• Turn the flow down for a betta, for fry or for shrimp. A small tank with a strong current is exhausting for the fish in it.
• Leave yourself room to lift it out, because a nano tank gives you very little working space.
• Never run it out of water. These pumps are cooled by the water they sit in.
• Rinse the foam in tank water only, and squeeze it gently.

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.
• A small tank is less forgiving than a large one, not more. A nano needs lighter stocking, lighter feeding and more regular water changes.
• Even with a fine intake, keep an eye on it in a tank with very young fry. A sponge pre-filter over the intake is cheap insurance.