An alternate system uses a fog or fine mist injected in to the intake air stream. Although many commercial systems are available, growers can assemble and install their own system using a ruthless piston pump and fog nozzles. The basic components are proven in Fig. 1. A two-stage system managed by a two- stage thermostat allows more water to be applied on excessively warm, bright days. Temperature settings should 
be 5-10°F apart.
Algae development in the pads can become a problem that may reduce the effectiveness of the system and lead to 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 water areas, to add a wetting agent to the water to obtain more uniform wetting of the pads. A commercial material or liquid home detergent at the price of 2 tablespoons per 100 gallons may be used.
Drinking water for the pads ought to be clean and lower in mineral content to avoid clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the water. A flow rate 113 gallon each and every minute per linear foot of pad system ought to be provided to make certain adequate wetting.
In the most common coolant system (fan and pad), the fans draw air through wet pads that prolong the length of one endwall or sidewall. Aspen and covered cellulose are common pad materials that always have life of 1 to 3 years. Approximately one sq . foot of pad are is needed for 20 square feet of floor area.
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