An alternate system uses a fog or great mist injected into the intake air stream. Although a number of 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 demonstrated in Fig. 1. A two-stage system managed by a two- stage thermostat enables more water to be applied on excessively warm, shiny days. Temperature settings should be 5-10°F apart.
Algae development in the pads may become a problem which will reduce 
the effectiveness of the machine and result in accelerated deterioration of the pads. The addition of an algaecide to the water supply will help in control.
It is desirable, especially in hard drinking water areas, to include a wetting agent to the drinking water to obtain additional 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 should be clean and lower 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 per minute per linear foot of pad program should be provided to guarantee adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that expand the length of 1 endwall or sidewall. Aspen and coated cellulose are common pad materials that always have life of one to three years. Approximately one square foot of pad are is needed for 20 square foot of floor area.
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