Achieve unparalleled precision and rock-solid reliability in your nutrient and chemical application with the 3/4" Mazzei Venturi Injector. Engineered for the tough demands of commercial agriculture, this injector provides a simple, maintenance-free solution for uniform fertigation and chemigation. Ensure your crops get exactly what they need, when they need it, with a system that harnesses the power of your existing water flow—no external power required.
Choosing the right injector is crucial for performance. An injector that is too large for your system's flow rate will fail to draw fertilizer, while one that is too small will restrict water flow. Use the table below to match your irrigation system's total Gallons Per Hour (GPH) to the correct 3/4" Mazzei model. Important: Sizing must be based on your system's actual water usage (total GPH of all emitters), not the capacity of your water source or the size of your main line pipe.
| Your System's Total Flow Rate (GPH) | Recommended 3/4" Model | Minimum Flow to Operate | Fertilizer Suction (GPH) @ 20 PSI Pressure Drop | Fertilizer Suction (GPH) @ 40 PSI Pressure Drop |
|---|---|---|---|---|
| 240 – 424 GPH | Low Flow (IM34L) | 240 GPH | 12 GPH | 17 GPH |
| 425 GPH and up | High Flow (IM34H) | 425 GPH | 21 GPH | 25 GPH |
| Below 240 GPH? | Consider a 1/2" Mazzei Injector for lower flow systems. | |||
*Data based on performance at 50 PSI inlet pressure. A pressure drop (differential) is the difference between the injector's inlet and outlet pressure.
To create a fully functional and controllable fertigation system, you will need three core components, which are sold separately as accessories:
1. The 3/4" Mazzei Injector Unit
Choose either the Low Flow or High Flow model based on your system's GPH.
2. A Bypass Assembly
This is the highly recommended method of installation. A bypass uses valves to divert a portion of the main water flow through the injector, allowing you to precisely control the pressure differential and, therefore, the suction rate. It also allows you to stop injection without affecting your main line's flow.
3. A Suction Assembly
This kit includes the tubing, valve, and weighted screen needed to connect the injector's suction port to your fertilizer tank. The screen prevents debris from clogging the injector.
Why is my new injector not drawing any fertilizer?
This is almost always due to an insufficient pressure differential (less than a 25–30% drop from inlet to outlet pressure).
If you are using a bypass, slightly close the main valve to force more water through the injector, which will increase the differential and initiate suction. Also, check that all connections on the suction line are airtight and that the suction screen at the bottom is not clogged.
Can I install this injector directly into my main water line?
While it is physically possible, we strongly recommend installing the injector on a bypass assembly.
A direct in-line installation may not create the necessary pressure drop for suction to occur and will cause a permanent pressure loss in your system. A bypass provides the control needed for accurate injection.
What kind of fertilizer can I use with this injector?
The Mazzei injector is designed for use with liquid concentrates or water-soluble fertilizers.
If using a powdered or granular fertilizer, ensure it is fully dissolved in your stock tank before injection to prevent clogging of the injector or your drip emitters. Fertilizers with less than 0.5% insoluble impurities are ideal.
Does the fertilizer tank need to be elevated?
While not strictly necessary if you have a strong pressure differential, elevating the fertilizer container can help reduce the amount of vacuum required to lift the solution.
This can improve suction performance, especially in lower-pressure systems.
Please keep the following in mind when selecting and installing your injector:
Build a fully functional injection setup with these recommended components and resources:
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