An alternate system runs on the fog or fine mist injected in to the intake air stream. Although 
a number of commercial systems can be found, growers can assemble and set up their own system utilizing a ruthless piston pump and fog nozzles. The basic components are demonstrated in Fig. 1. A two-stage system managed by a two- stage thermostat Greenhouse Exhaust Fan enables more water to be employed 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 machine and result in 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 drinking water areas, to include a wetting agent to the water to obtain additional 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 prevent 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 ought to be provided to make certain adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that prolong 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 sq . foot of pad are is necessary for 20 square ft of floor area.