Most automated systems installed in closed hydroponic systems use injectors rather than proportioners. A simplified diagram of where to install such a system is provided below. Many advanced injectors such as the Priva® and Volmatic® systems use much more complex configurations. Most of the systems use two pH probes and two EC probes in case the one is faulty. In this case the computer is set to compare both probes and if the difference exceeds a set value, an alarm will be triggered to notify the grower. Note the pH and EC probes are placed in the blending tank, however, many systems have the probes between the blending tank and injector. The placement of the pump is also relative. Some systems have the pump as in the diagram but others prefer the pump after the blending tank. In closed hydroponic systems the use of some form of sterilization is important. It is recommended that if a large systems are used both UV and Ozone sterilization are installed. In the diagram only three tanks are installed, some growers would prefer more, for instance some growers prefer Tank A for most macro and micro nutrients, Tank B for calcium nitrate and Fe chelate, Tank C for potassium nitrate or sulphate to boost the plant with and Tank D for additional micronutrients Most systems are designed to manage five tanks with on for the pH. The water supply should be fed into the main nutrient tank connected to a float valve to ensure the water level stays constant.
I studied agriculture at the University of Stellenbosch in South Africa in 1984 and completing my M.Sc Agric. in 1998. . My love for "Controlled Environmental Agriculture" (CEA), started in my third year when I was exposed to the Welgevallen Research Station. There Prof. P.C.Maree showed us what hydroponics consisted of. It was awesome. There were no large tractors involved, no dusty fields, no uncontrollable storms to destroy your crop (well that is what I thought). Since then I put hydroponics to much better use, not just farming. We solved pollution problems by cleaning mines effluent with hydroponics and aquaculture. They were used to remove toxic metals to produce clean water (which we sold and make more money of than the produce). What I learned from 1987 I tried to compile in this website and I hope it is from some value to the serious commercial farmer that wants to take the journey into Commercial Hydroponic Farming.
Calcium and Boron have a close relationship in the plant. Their absolute concentrations and the