mynd said:It is not that big, but big enough I would not want it hanging off my tank. The nice thing to use it for is cleaning day.. I would do a water change, blow off all the rock and the bottom of the tank ( bare bottom ) and all the debris would just get sucked up by it. Very nice for cleanings.. Leave it on for an hour and just keep ( turkey basting ) the entire tank ( pristine water conditions ) Then I would take it off, clean it out and put it away until the next time. Great unit..