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Originally Posted by harveyc
It is pretty difficult to know how the injector is designed without looking at it and taking it apart. According to the manufacturer, it is proportioning and the 1.5 quart model requires 75 gallons of flow for the fertilizer to be dispersed.
http://fertilizerdispensers.com/serv...portioning.pdf
http://fertilizerdispensers.com/serv...hure_table.pdf
Even if most of the fertilizer solution did get dispersed in the first 10% of the irrigation, the majority of that would not go to the first outlet unless you only had two outlets.
I cannot recommend the product without having more information or personal experience with it. |
In the product description, you can read that
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The amount of fertilizer or additive concentrate dispensed from the tank will be directly proportional to the volume of water entering the injector, regardless of variations in flow or pressure, which may occur in the main line. The injection rate is preset at a ratio of 200:1 (200 parts water to 1 part additive).
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This means that contents of the dispenser are continuously diluted. The more flow that passes through the system the weaker the concentration becomes. For the 1.5 quart size container, total replacement occurs at 200 x 1.5 qts = 300 qts = 75 gallons of flow. However, the concentration will drop geometrically and the concentration will be at 50% after the first 10% of flow; i.e., 7.5 gallons. Further, a typical irrigation pipe has a 5 gallon capacity from the valve to the 1st sprinkler head/drip outlet so the majority of the 7.5 gallons will be disbursed to the 1st outlet while the remaining outlets will receive the fresh water that was ahead of it in the pipe. After that, all outlets receive diminishing returns.
For a number of years the EZ-Flo company received criticism for this kind of design and the behavior I describe above was reported by a number of studies by universities and manufacturers alike. Finally, EZ-Flo modified it's design with a feedback loop to offset the geometric progression. It works a little better now. Still, no one in professional agriculture uses them. The choice for small scale systems is Venturi suction (e.g., devices made by Dramm and Grow More) and for larger scale the choice is water pressure driven pump injectors (e.g., Dosatron and Dosmatic).