Comments on the April 5, 2006 Graph

The heaters are set at 60 deg F, with a hysteresis of +/- 1 F deg ( The heaters turn "on" at 61 deg F and turn "off" at 59 deg F).

The vent fans are set at 80 deg F, with a hysteresis of +/- 1 F deg.

Note the "steps" in nutrient solution temperature, coinciding with nutrient solution pump cycles. Increases of up to 9 F degrees (on sunny days) have been observed in Late March and early April. Since the nutrient solution storage tanks are located inside the greenhouse, this heat is released in the greenhouse (when greenhouse air temperature drops below that of the nutrient solution).