This type of system works by temporarily flooding the grow tray with nutrient solution, and then draining the solution back into the reservoir. This is normally done with a submerged pump. There are many different kits you can mix and match to build the right garden kit for your plants using this style. It is very versatile with different types of growing media.* Available in black * Sturdy polystyrene construction * Ridged for excellent drainage and aeration Easy to clean and maintain * Most popular with rockwool cubes * Also ideal for mesh pots and Hydroton expanded clay pellets