G.A.S Intelligent Humidity Controller (For Sonic Air Pro)INTELLIGENT HUMIDITY CONTROLLER (FOR SONIC AIR) THE G. A. S INTELLIGENT HUMIDITY CONTROLLER SONICAIR PRO IS FOR USE WITH SONICAIR PRO ONLY! The Intelligent Humidity Controller monitors your grow room environment and controls the humidity levels to VPD (vapour pressure deficit) or relative humidity. Humidity is complicated business in grow rooms. Dry air allows water to evaporate, which leads to your plants transpiring or water evaporating from the