Review on Aquarium Gravel & Sand Cleaning Vacuum: Laifoo Siphon for Fish Tank Maintenance by Maria Campbell

Not sure what it's designed for. There's a weird filter screen that blocks almost any dirt from going through the pipe. Removing this liner will improve water flow significantly, however, there is now a problem with the length of the stiffest siphon tube: it is too short for the gravel that has accumulated to settle back into the aquarium floor. Gravel immediately clogs the tube and you were instructed to disassemble the whole thing, clear the blockage and start the process over. This is the most annoying gravel siphon I've dealt with in ten years of aquarium existence.