Iron makes up at least 5% of the earth’s crust. Rainfall seeping through the crust dissolves this iron and transports it into water sources, so, generally all groundwater sources will contain some level of dissolved iron.
In a process known as precipitation, oxygen in the air reacts with dissolved iron in the water and causes it to become insoluble, forming an insoluble reddish-brown sediment. Levels of soluble iron in water above 1 mg/L (parts per million (ppm)) will cause excessive sediment and growth of slime (biofilm)leading to:
• Blocked drippers, filters and spray nozzles ;
• Scale build-up in irrigation pipes;
• Reduced irrigation efficiency through reduced flow and pressure;
• Increasing maintenance and replacement costs;
• Staining of nursery structures, plants and containers.