An alternate system uses a fog or great mist injected into the intake air stream. Although many commercial systems can be found, growers can assemble and install their own system utilizing a high pressure piston pump and fog nozzles. The basic components are demonstrated in Fig. 1. A two-stage system controlled by a two- stage thermostat enables 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 which will reduce the effectiveness of the machine and lead to accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply can help in control.
It is desirable, especially in hard water areas, to add a wetting agent to the water to obtain additional uniform wetting of the pads. A commercial materials or liquid household detergent at the rate of 2 tablespoons per 100 gallons can be used.
Drinking water for the pads should be clean and low in mineral content to avoid clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the drinking water. A flow rate 113 gallon per minute per linear foot of pad program ought to be provided to make sure adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that extend the length of 1 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 ft of floor area.
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