Gravel vacuum (siphon)
Wide bell tube used to vacuum debris from the substrate during water changes. The most used maintenance tool.
Detailed explanation
The siphon (gravel vacuum) is composed of a tube with a large bell at the end. The siphon starts and gravity does the rest.
The wide bell allows it to sink into the substrate, sucking up debris without taking away the gravel. The bell is pressed into the gravel, the debris is sucked up, the gravel falls back.
With fine sand you need to be more delicate: the bell should be held slightly above the surface so as not to suck in the sand.
The siphon is also the most efficient way to do water changes: it sucks the old water from the bottom while simultaneously collecting the debris.
Models with non-return valve and starter pump (Python, Aqueon Water Changer) connect directly to the tap for draining and filling.