The Water Flow Assembly Replacement Part Fits The Aqueon Aquarium Water Changers Used For Connecting Tubing To The Faucet For Water Changes Has A Built In Onoff Valve To Drain Water From And Return Clean Water To The Aquarium Be Sure To Add Aqueon Water Conditioner When Adding Clean Water To Aquariumthe Aqueon Aquarium Water Changers Are Designed To Help Eliminate The Potential For Messy Aquarium Spills And Transporting Heavy Buckets Of Water Simply Attach The Water Flow Assembly To The Faucet Using The Included Multi-Connection Faucet Adaptor And Turn On The Faucet (See Diagram For Faucet Types) Aquarium Water Changer Can Be Used To Remove Water As Well As Add Water Back Into Aquarium It Makes Routine Water Changes Easier And Also Vacuums Out The Debris In The Gravel By Adjusting The Flow Direction, Clean Water Can Easily Be Added Back To The Aquarium Developed By True Aquatic Hobbyists, Aqueon Provides A Broad Array Of Aquarium Solutions To Help Maintain Healthy, Life-Sustaining Aquatic Environments