Light
will accelerate the growth of algae and pathogens. Further, some brands of
chelated trace elements can decompose from exposure to UV light which causes
them to become unavailable for root up-take. Therefore minimize exposure to
light as much as possible by placing a lid on the nutrient reservoir, and
other regions of the system where nutrient is exposed to direct light.
However in
achieving this, ensure the design allows adequate ventilation of air
otherwise this air will become humid and susceptible to disease. For
example, when placing a lid on the reservoir, have it in a raised position
so that air can freely enter and exit (Fig 6.5).
