This 8 m long extension was actually designed for the JBL PROCLEAN AQUA IN-OUT water change set, but can also be used for any other 12/16 hose. It also fits the previous model: JBL Aqua In-Out.

Regular water changes
Food, plant remains and metabolic products pollute the aquarium water. Because aquarium filters cannot completely remove these substances from the water and a large part of the dirt ends up in the bottom substrate, a partial water change must be carried out regularly (approximately 1/3 of the water content every 2 weeks). The water change must always be connected to the extraction of the substrate. After a water change, a good water conditioner such as JBL Biotopol must be used to make the new tap water fish-friendly.

This is how the aquarium bottom is properly cleaned:
Move the mole clock (JBL PROCLEAN AQUA IN-OUT or JBL PROCLEAN AQUA EX) into the substrate of your aquarium in a circular motion. The suction force pulls the substrate and dirt up in the bell. Due to its own weight, the substrate falls back and only the dirt is sucked out of the aquarium. For fine sand you can adjust the suction force by lifting the mole bell so that the light sand also falls down again. A sieve in the bell prevents accidental sucking in of fish and shrimp. The sieve can be removed for cleaning.
If there is a long-term soil fertilizer under the opaque gravel layer (e.g. JBL PROFLORA AQUA BASIS), the mole cap should not be pressed into the substrate all the way to the bottom, but only into the opaque soil layer.