Most aquarium gravel vacuums are a wide, rigid, clear tube, typically about 2" in diameter, attached to a narrower siphon tube , typically about 1/2" in diameter.

A gravel vacuum uses the action of the water flowing through the siphon (and through the gravel to get into the siphon) to loosen debris from the gravel and remove that debris and solid waste from your fish tank as you remove old water to be replaced.

This is an important part of your routine aquarium maintenance as it removes this decaying debris from the tank and clears the channels through the gravel, making your under gravel filter more efficient (if you are using one) and preventing the development of anaerobic pockets in the aquarium gravel. If these anaerobic pockets develop, they can release toxins into the aquarium water, which can harm or kill your fish or biological filter .

What Are Gravel Vacuums For?

Gravel vacuums are used when performing your regular weekly 10-15% water change to clean part of the gravel while removing the water. This is important in all aquariums, but is particularly important in an aquarium with an under gravel filter ....