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 install their own system utilizing a high pressure piston pump and fog nozzles. The essential components are shown in Fig. 1. A two-stage system controlled 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 can become a problem that will reduce the effectiveness of the system and result in accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply will help in control.
It is desirable, especially in hard water areas, to add a wetting agent to the drinking water to obtain more uniform wetting of the pads. A commercial material or liquid household detergent at the price of 2 tablespoons per 100 gallons may be used.
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 per minute per linear foot of pad system should be provided to assure adequate wetting.
In the most common cooling system (fan and pad), the fans draw air through wet pads that expand the length of 1 endwall or sidewall. Aspen and covered cellulose are common pad materials that usually have life of one to three years. Approximately one sq . foot of pad are is needed for 20 square ft of floor area.
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