An alternate system runs on the fog or fine mist injected into the intake air stream. Although many commercial systems are available, growers can assemble and set up their own system using a ruthless piston pump and fog nozzles. The basic components are shown in Fig. 1. A two-stage system controlled by a two- stage thermostat enables more water to be applied on excessively warm, bright days. Temperature settings should be 5-10°F apart.
Algae development in the pads may become a problem that may reduce 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 really is desirable, especially in hard drinking water areas, to include a wetting agent to the water to obtain more uniform wetting of the pads. A commercial material or liquid household detergent at the rate of 2 tablespoons per 100 gallons can be used.
Drinking water for the pads ought to be clean and lower 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 system 
should be provided to guarantee adequate wetting.
In the most common coolant system (fan and pad), the fans draw air through wet pads that expand the length of one endwall or sidewall. Aspen and covered cellulose are normal pad materials that always have life of 1 to 3 years. Approximately one sq . foot of pad are is needed for 20 square ft of floor area.
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