Durable, flexible, and easy-to-plumb polyethylene tubing ideal for aquarium reverse osmosis applications. AquaticLife 1/4" Polyethylene Tubing, Red is nontoxic and highly resistive to stress cracking from liquid. Use red, color-coded tubing to indicate wastewater discharge line. Plumb from wastewater port on your reverse osmosis or deionization unit to a drain or secured in a way to handle the wastewater. 1/4" x 50 ft.