An alternate system runs on the fog or fine mist injected into the intake air stream. Although a number of commercial Greenhouse Auto Vent systems are available, growers can assemble and set up their own system utilizing a ruthless piston pump and fog nozzles. The essential components are proven in Fig. 1. A two-stage system managed by a two- stage thermostat enables more water to be employed on excessively warm, bright days. Temperature settings ought to be 5-10°F apart.
Algae growth in the pads can become a problem that will decrease the effectiveness of the machine and lead to accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply will help in control.
It really is desirable, especially in hard water areas, to add a wetting agent to the water to obtain more uniform wetting of the pads. A commercial materials or liquid household detergent at the price of 2 tablespoons per 100 gallons can be used.
Drinking water for the pads ought to be clean and low in mineral content to prevent clogging and coating of the pads. A pump, pipes and gutters are used to recirculate the water. A flow rate 113 gallon 
each and every minute per linear foot of pad program should be provided to assure adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that lengthen the length of 1 endwall or sidewall. Aspen and covered cellulose are common pad materials that always have life of 1 to three years. Approximately one square foot of pad are is necessary for 20 square foot of floor area.