Lees Ultra Gravel VacLees new Ultra Gravel Vac Self Start Siphon feature has made aquarium maintenance a whole lot easier! With the Gravel Vacuum cylinder submerged in the water, simply move it up and down a few times to activate the Self Start Siphon. Separates and removes debris from aquarium Drains and fills for routine water changes Self starting siphon Gravel Vacuum Cleaners are designed to separate and remove debris from the aquarium during routine water changes.