Independent studies by a major UK research company show that Pumice Horticultural Media is the most effective product to be used for Hydroponics. The photo below shows the growth rate of the plant in 5 different medias. Pumice Horticultural media is second on the right showing the best growth rate in fresh and dry conditions;
Also below is a Apogee Plant Graph showing the performance of Pumice media against it competitors. You can see the pumice not only recorded best growth but also had the best recovery rate out of all 5 products used. The insulating properties of pumice make it ideal for roof systems by helping reduce heating costs in winter and assisting with cooling during summer. Also this property increases the temperature of the plant food favouring plant nutrition and growth.