Aquael flexible cleaning brush for filter pipes, 9 to 30 mm

The bottle brush consists of a flexible braided wire shaft, which follows the curves of the pipe without piercing it, and two soft-bristled heads. The small 9 mm head fits into narrow pipes, suction tubes and diffuser manifolds, while the large 30 mm head cleans the wide pipes of external filters and pond pumps. For each pipe, choose the head whose diameter is closest to its inside diameter. The bristles scrub the wall without scratching it, which avoids creating rough spots where deposits would then build up faster. For short, rigid parts, such as strainers or elbows, the 37 cm Hobby brushes are easier to handle.

Unplug the filter and close its taps if it has any, then detach the pipes and empty them into a bucket. Push the bottle brush in at one end and work it along, turning it slightly, until it comes out the other side, then pull it back. Next, rinse the pipe under running water to flush out the loosened deposits, and check the seals and fittings while you are at it, as they get clogged too. When you restart, a few air bubbles will escape from the filter for a few minutes, which is normal. Finally, rinse the bottle brush in clean water and leave it to dry, head down, before putting it away.

The right moment to get out the pipe brush shows in the flow rate. A transparent pipe reveals its condition, since a greenish or brownish film on its inner wall signals that it is time to brush it; an opaque pipe is better judged by the return outlet. Time how long it takes to fill a one-litre container just after a full maintenance session, then repeat the measurement from time to time: when filling takes noticeably longer even though the media have just been rinsed, it is the pipes of your filter that are holding the water back. In most circuits, this brushing comes round every 3 to 6 months. Spray bars should also be watched, as their small holes clog up one after another: the 9 mm head goes inside, and a fine needle then clears each hole.