Tefen TF Fertiliser Dosing Pumps: Which Model Is Right for Your System?
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Introduction
The Tefen TF series of fertiliser dosing pumps is one of the most popular ranges of water-powered injectors used in UK horticulture and agriculture. Compact, robust, and requiring no electricity, TF pumps deliver proportional fertigation across a wide range of flow rates — from small greenhouse bays to large-scale farm irrigation systems.
Unlike venturi injectors, which rely on a pressure differential to draw fertiliser by suction, the Tefen TF pumps use a water-driven piston mechanism to deliver a precisely metered dose of fertiliser concentrate for every volume of water that passes through the unit. This proportional dosing principle ensures a consistent fertiliser concentration regardless of changes in flow rate — a significant advantage over simple venturi systems in applications where precise nutrition is important.
This guide covers how TF pumps work, the full model range, and how to choose the right unit for your system.
How Tefen TF Dosing Pumps Work
The TF pump operates on a hydraulic piston principle:
- Water enters the pump body and drives a piston back and forth as it flows through
- Each stroke of the piston draws a precise volume of fertiliser concentrate from the stock tank via a suction tube and check valve
- The fertiliser is injected into the water stream downstream of the piston and mixed before exiting the unit
- Because the piston is driven by the water flow itself, the volume of fertiliser injected is always proportional to the volume of water passing through — the injection ratio remains constant even as flow rate changes
This proportional dosing is the key advantage of the TF pump over a simple venturi injector. It makes the TF range particularly well suited to applications where consistent nutrient delivery is critical, such as hydroponic systems, propagation, and high-value greenhouse crops.
The Tefen TF Model Range
The TF range covers five models, each designed for a different flow rate range. Choosing the correct model is essential — operating a TF pump outside its rated flow range will result in inaccurate dosing or damage to the unit.
Tefen TF 1
The smallest model in the range, designed for very low flow rate applications such as individual greenhouse bays, propagation benches, or small pot plant areas.
- Flow rate range: suitable for low-flow zones and small systems
- Best for: propagation, small greenhouse sections, individual crop trials
- Injection ratio: fixed proportional dosing
Tefen TF 3.5
A step up from the TF 1, suitable for slightly larger zones or where a higher flow rate is needed while maintaining precise dosing accuracy.
- Best for: medium greenhouse bays, nursery benches, small polytunnel zones
Tefen TF 5
One of the most widely used models in UK horticulture, the TF 5 suits a broad range of greenhouse and nursery applications where moderate flow rates are involved.
- Best for: greenhouse production zones, nursery stock areas, polytunnel irrigation, pot plant production
Tefen TF 10
Designed for larger zones and higher flow rate systems, the TF 10 is suitable for main supply lines serving multiple greenhouse bays or larger outdoor production areas.
- Best for: multi-bay greenhouses, larger nursery operations, outdoor field irrigation headers
Tefen TF 25
The largest model in the TF range, designed for high flow rate main lines and large-scale irrigation systems where proportional dosing accuracy is required across significant volumes of water.
- Best for: large farm irrigation systems, main supply headers, high-volume greenhouse complexes
Browse the complete Tefen range including all TF models and spare seal kits.
How to Choose the Right TF Model
The single most important factor in selecting a TF pump is matching the model to your system's flow rate. Here is a simple process:
- Measure your flow rate — use a flow meter or calculate from your pump output and zone size. Express this in litres per hour.
- Check the model specifications — each TF model has a rated flow range. Select the model whose range covers your actual flow rate.
- Consider future expansion — if you plan to increase your irrigated area, choose a model with headroom above your current flow rate.
- Check your injection ratio requirement — confirm the model's injection ratio matches your fertiliser programme's dilution requirements.
If you are unsure which model is right for your system, contact the IrriSmart team for advice — we are happy to help you specify the correct unit based on your system design.
Installation
TF pumps are designed for straightforward inline installation:
- Install the pump inline on the irrigation supply pipe serving the zone to be fertigated
- Connect the suction tube to your fertiliser stock tank using the supplied fittings
- Ensure the stock tank is positioned at or below the level of the pump suction port
- Install a check valve upstream of the pump to prevent backflow into the mains supply — this is a legal requirement under the Water Supply (Water Fittings) Regulations 1999 when connected to mains water
- Install a filter upstream of the pump to protect internal components from particle damage — our Amiad Filters range includes compact inline options suitable for fertigation stations
- Flush the system with plain water before introducing fertiliser to confirm correct operation
- Verify output concentration with an EC meter and adjust stock solution concentration if needed
Maintenance and Spare Parts
Tefen TF pumps are low maintenance but benefit from an annual service, particularly if used with concentrated fertiliser solutions:
- Flush thoroughly with clean water at the end of each irrigation season
- Inspect and clean the suction strainer
- Check internal seals and diaphragms for wear — seal kits are available for all TF models
- Store in a frost-free location over winter
Replacement seal kits for the TF range are available from IrriSmart — the Tefen Spare Seal Kits keep your pump performing accurately season after season and are a cost-effective alternative to full unit replacement.
TF Pumps vs Dosatron: A Quick Comparison
Both the Tefen TF range and the Dosatron range are water-powered proportional dosing pumps operating on similar principles. Key differences to consider:
- Price point: Tefen TF pumps are generally more competitively priced, making them an attractive option for budget-conscious operations or where multiple injection points are needed
- Range: Dosatron offers a broader range of models and accessories; Tefen TF covers the most common horticultural flow rate requirements very effectively
- Spare parts: both ranges have readily available seal kits and service parts
- Performance: both deliver reliable proportional dosing suitable for professional horticultural use
Conclusion
The Tefen TF range offers professional-grade proportional fertigation at a competitive price point, making it an excellent choice for growers who need accurate, reliable dosing without the cost of a full automated fertigation system.
With five models covering a wide range of flow rates, there is a TF pump to suit everything from a single propagation bench to a large farm irrigation header. Browse the full Tefen TF range online, or get in touch with the IrriSmart team for help choosing the right model for your system.