The Active Aqua Root Spa is a Deep Water Culture System. These 5 gallon bucket systems are simple and grows large plants efficiently. You will quickly realize the advantage of the simplicity of this easy to use, inexpensive, and no hassle system! Pumping raw air into the nutrient solution without the need of expensive and often troublesome air stones is both cost effective and easy. You can use your choice of hydroponic media (sold separately), such as clay pebbles, Number 4 perlite, rockwool mini cubes, coco chips, etc. Since this is a hydroponics system, soil should be avoided. Soil may contain dust, fungi, and bacteria, all of which can contaminate the hydroponics system.