JBL Filterbag Fine

JBL Filterbag Fine is a nylon mesh bag for loose filter media. It holds between half a litre and one and a half litres, and the mesh is 0.5 by 0.5mm, which is fine enough to keep small granules in while still letting water through.

Key Features

• Holds 0.5 to 1.5 litres: JBL's figure, which covers most loose media you would buy by the bag.
• 0.5 by 0.5mm mesh: fine enough for small granules, open enough not to choke the flow.
• Water-neutral nylon: JBL specifies a material that releases nothing into the water.
• Makes media changes simple: lift a bag out instead of scooping granules from a basket.
• Keeps media out of the impeller: loose granules that escape a basket end up in the pump.
• Reusable: rinse it out and refill it.

Using It

• Do not overfill it. Media needs water moving through it, and a bag packed tight diverts the flow round the outside instead.
• Tie or close it properly before it goes in, and check it has not worked open at each service.
• Rinse a bag of biological media in tank water only. Tap water kills what is living on it.
• Label bags if you run more than one medium, because granules are hard to tell apart once they are wet.

Good To Know

• Rinse media in tank water, never under the tap. Chlorine kills the bacteria living on it, and those bacteria are most of what a mature filter is worth.
• Media only works if water goes through it rather than round it. Fit it so it fills its basket without being rammed in, and check flow afterwards.
• Put the coarse mechanical stages first in the flow and the fine or chemical media later. Fine media placed first just blocks.
• Replace the bag when the mesh starts to go. A split bag empties its media into the filter housing.
• A fine mesh clogs with silt in a dirty filter. Keep the coarse mechanical stages ahead of it and the bag stays clear much longer.