Siphon-Kleen removes accumulated waste, leaving the gravel bed open to oxygenated water flow and increased aerobic bacterial action. Periodic water changes (20% each month) with Siphon-Kleen help keep aquarium water sparkling clean--free of toxic ammonia and nitrites. Siphon Kleen draws water at a velocity proper for ensuring that grunge, not gravel, is removed. Includes six feet of hose. Opti-Flow Cone improves gravel cleaning and water siphoning performance. Angle-cut end grabs more grunge.