A hydroponic stone substrate is the perfect growing media for use in hydroponic growing systems
The water storage is low but the air content of the bed and the drainability are very high. pH neutral types should be used.
The optimal supply of nutrients and oxygen to the roots is the main reason for faster and more vigorous plant growth in hydroponic systems compared to cultivation in soil.
Clay balls are easy to use and can be rinsed and reused frequently.