An alternate system runs on the fog or great mist injected into the intake air stream. Although a number of commercial systems are available, growers can assemble and set up their own system utilizing a ruthless piston pump and fog nozzles. The essential components are shown in Fig. 1. A two-stage system managed by a two- stage thermostat allows more water to be applied on excessively warm, shiny days. Temperature settings ought to be 5-10°F apart.

Algae development in the pads may become a problem that will decrease the effectiveness of the system and result in accelerated deterioration of the pads. The addition of an algaecide to the water supply can help in control.

It is desirable, especially in hard water areas, to include a wetting agent to the water to obtain more uniform wetting of the pads. A commercial material or liquid home detergent at the rate of 2 tablespoons per 100 gallons can be used.

Drinking water for the pads ought to be clean and low in mineral content to avoid 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 Greenhouse Auto Vent minute per linear foot of pad system should be provided to guarantee 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 coated cellulose are common pad materials that always have life of one to 3 years. Approximately one square foot of pad are is necessary for 20 square feet of floor area.