Short answer: Dosing pumps fall into three types by operating principle: electromagnetic (solenoid) diaphragm, mechanical (motor-driven) diaphragm and peristaltic. Chlorine dosing pump models are further divided by control type: manually adjusted analogue, level control, timer, volumetric (water meter input), pH/ORP measurement and free chlorine measurement. AnTech’s Nova, Lara, Optima and Nano series include 38 electromagnetic models covering these control types, with nominal flow rates of 2–25 L/h and back pressures of 5–20 bar.
On this page we first compare the pump types, then set out the control types and every model in the AnTech series in table form. All technical data is taken from the AnTech 2025 catalogue. Before choosing a chlorine dosing pump, you can work out the flow rate you need with our chlorine dosing calculator.
Types of Dosing Pump: Electromagnetic, Mechanical Diaphragm and Peristaltic
Dosing pumps come in three types according to how they push the chemical. The choice is mostly determined by the required flow rate, the line pressure and whether the chemical gives off gas.
Electromagnetic (solenoid) diaphragm dosing pump
Operating principle: An electronic board drives the electromagnet in the pump with short pulses. With each pulse the PTFE diaphragm is pushed forward and the chemical in the head leaves through the discharge check valve; as the diaphragm retracts, the suction check valve opens and the head refills. The flow rate is adjusted by changing the number of strokes per minute.
Advantages: Compact and lightweight (1.76–2.9 kg for AnTech models), with low power consumption (10–27 W). Thanks to electronic control it can be linked to a water meter, a 4–20 mA signal, or pH, ORP and free chlorine measurement. Fine adjustment is possible at low flow rates.
Limitations: Flow is limited to a few tens of litres per hour and decreases as back pressure rises. Gas released by sodium hypochlorite can get trapped in the small check valves and stop dosing (gas locking), which is why the air-bleed connection on the head is important.
Mechanical (motor-driven) diaphragm dosing pump
Operating principle: An electric motor moves the diaphragm continuously through a mechanical drive. In the AnTech EMD series, capacity is adjusted manually in the 0–100% range while the pump is running or stopped; it can also be adjusted with a motor drive that accepts a 4–20 mA signal input.
Advantages: Delivers high flow rates (14–630 L/h at 50 Hz in the EMD series). Head and ball materials are chosen to suit the chemical: PP, PVC, PVDF or stainless steel (SS316) heads; ceramic, Pyrex or stainless steel balls. The diaphragm is PTFE on all models.
Limitations: Considerably more expensive than analogue electromagnetic pumps, and installation requires more engineering: a solid base is needed, the motor must be connected by a qualified electrician, and fitting a pressure relief valve on the discharge line is recommended. Oversized for doses of a few litres per hour.
Peristaltic dosing pump
Operating principle: Rotating rollers squeeze a flexible hose and move the chemical inside it forward. The only part inside the pump that comes into contact with the chemical is the hose.
Advantages: Has an advantage against the gas locking seen in diaphragm pumps, so it is preferred for chemicals that release gas. Very low flow rates can be set: the lower limit on the Aspendose DMS and PR models is 0.001 L/h. Maintenance is easy because the wear part is the hose.
Limitations: Back pressure ratings are low; a maximum of 3 bar in the Aspendose series. The hose loses its elasticity over time and has to be replaced. According to a catalogue note, sodium hypochlorite of up to 16% is used for chlorine dosing.
Comparison table
| Feature | Electromagnetic | Mechanical diaphragm | Peristaltic |
|---|---|---|---|
| AnTech series | Nova, Lara, Optima, Nano | EMD-P, EMD-M | Aspendose |
| Flow rate | 2–25 L/h nominal | 14–630 L/h (50 Hz) | 0.001–5.1 L/h |
| Max. back pressure | 5–20 bar | 3–7 bar | 0.5–3 bar |
| Flow adjustment | Stroke rate (adjustment knob or menu) | Manual 0–100% or 4–20 mA motor drive | Adjustment knob or digital menu |
| Supply / power | 230 V AC or 95–260 V AC, 10–27 W | Electric motor, 0.09–0.37 kW | 95–260 V AC; AC 100–240 V or DC 12–28 V on DMS and PR |
| Wear parts | Diaphragm, check valve, O-ring | Diaphragm, check valve | Hose |
| Best suited to | Small and medium-flow chlorination, measurement-controlled dosing | Municipal and industrial plants, high flow | Gas-forming chemicals, low pressure, very low flow |
Dosing Pump Models by Control Type
Within the same pump type, the main feature that sets models apart is how dosing is controlled. AnTech’s electromagnetic series offer six control types, all listed in the electromagnetic dosing pumps category.
Analogue (manual adjustment)
The flow rate is set manually by changing the stroke rate with the adjustment knob on the front panel; there is no display or menu. It is the simplest solution for small and medium installations with a constant flow rate. The models in this group are the Lara A, Optima A and Nano A; level control is not listed among the features of any of the three. Example: AnTech Lara A 2 L/h 10 Bar.
Analogue with level control
Liquid level control is added to analogue operation: a suction assembly with a level sensor signals the pump when the chemical in the tank runs low. The Lara APS has a 1/10 fine adjustment step and the Nova A has 1/10 and 1/100 steps; these make adjustment easier at very low flow rates. The Nova A has two level inputs and adapts automatically to 95–260 V AC mains.
Digital, timer-controlled
A digital display and microcontroller allow the flow rate to be entered precisely, and the pump runs to a set time programme. This suits applications where the chemical has to be dosed at specific times, such as tanks that run during filling hours. On the Lara DS, two BNC inputs can be configured for level or flow control, and a user password protects the settings. The Nova D, DMPR and DMİA also offer real-time clock, periodic and trigger-input operating modes.
Volumetric (water meter input)
The pump works on the signal from a water meter or flow meter with a signal output and doses chemical in proportion to the water passing through; even if the line flow changes, the chlorine concentration in the water stays constant. The AnTech Lara DMS 5 L/h 7 Bar has a 4–20 mA analogue input and a liquid level alarm relay. The AnTech Nova D 10 L/h 10 Bar offers a volumetric ppm mode and 4–20, 20–4, 0–20 and 20–0 mA analogue control. Suitable for well and mains lines whose flow varies during the day.
pH/ORP measurement
The pump measures the pH or ORP (redox) value of the water with a standard combination electrode and adjusts the dose according to how far the measured value is from the target. ORP shows the oxidising power of the water in mV and rises as free chlorine increases; because it is also affected by pH, keeping pH stable is recommended in systems where chlorine is dosed by ORP. The models in this group are the AnTech Lara PR 5 L/h 7 Bar, which is calibrated digitally with buffer solutions, and the Nova DMPR with a 4–20 mA measurement output; electrode sets are selected separately. The models are listed in the pH/ORP controlled dosing pumps category; for pH applications, see our pH dosing pump page.
Free chlorine measurement
The AnTech Nova DMİA 10 L/h 10 Bar and the other capacities of the same type measure the free chlorine level of the water directly in mg/L (ppm) with an amperometric sensor and adjust the dose to that value. With a suitable sensor they are also used to measure chlorine dioxide, hydrogen peroxide and peracetic acid. The sensor is selected separately according to the measuring range: a 0–2 ppm or 0–5 ppm selective sensor, or a 0–10 ppm amperometric cell. Developed for drinking water tanks and food and process plants; the models are in the dosing pumps with chlorine measurement category.
AnTech Chlorine Dosing Pump Models: Series by Series
In AnTech’s electromagnetic series, each control type is offered in several capacities. In the Nova and Lara tables, rows show the control type and columns show the capacity; each cell contains a link to the product page and the current price excluding VAT.
Nova series (95–260 V AC, 2.9 kg)
| Control type | 3.5 L/h · 20 bar | 10 L/h · 10 bar | 25 L/h · 5 bar |
|---|---|---|---|
| Nova A: analogue, level control | Nova A 3.5 L/h 20 Bar $646.85 |
Nova A 10 L/h 10 Bar $596.58 |
Nova A 25 L/h 5 Bar $712.77 |
| Nova D: digital, volumetric | Nova D 3.5 L/h 20 Bar $754.10 |
Nova D 10 L/h 10 Bar $702.71 |
Nova D 25 L/h 5 Bar $821.14 |
| Nova DMPR: pH/ORP measurement | Nova DMPR 3.5 L/h 20 Bar $986.48 |
Nova DMPR 10 L/h 10 Bar $936.21 |
Nova DMPR 25 L/h 5 Bar $1,052.39 |
| Nova DMİA: free chlorine measurement | Nova DMİA 3.5 L/h 20 Bar $1,002.12 |
Nova DMİA 10 L/h 10 Bar $952.96 |
Nova DMİA 25 L/h 5 Bar $1,068.04 |
Nova models share the same housing; a wall-mounting kit and mounting foot are supplied with the pump. Digital Nova models have level, flow and PT100 inputs; ModBus RTU (RS485) communication is provided with a separately sold module. Series details are on the AnTech Nova series page.
Lara series (230 V AC, 17 W, 2.2 kg)
| Control type | 2 L/h · 10 bar | 5 L/h · 7 bar | 10 L/h · 5 bar | 2 L/h · 20 bar |
|---|---|---|---|---|
| Lara A: analogue | Lara A 2 L/h 10 Bar $306.11 |
Lara A 5 L/h 7 Bar $306.11 |
Lara A 10 L/h 5 Bar $380.96 |
Lara A 2 L/h 20 Bar $414.48 |
| Lara APS: level control | Lara APS 2 L/h 10 Bar $396.60 |
Lara APS 5 L/h 7 Bar $396.60 |
Lara APS 10 L/h 5 Bar $471.45 |
Lara APS 2 L/h 20 Bar $504.97 |
| Lara DS: digital, timer | Lara DS 2 L/h 10 Bar $449.11 |
Lara DS 5 L/h 7 Bar $449.11 |
Lara DS 10 L/h 5 Bar $522.85 |
Lara DS 2 L/h 20 Bar $556.36 |
| Lara DMS: digital, volumetric | Lara DMS 2 L/h 10 Bar $489.33 |
Lara DMS 5 L/h 7 Bar $489.33 |
Lara DMS 10 L/h 5 Bar $564.18 |
Lara DMS 2 L/h 20 Bar $597.70 |
| Lara PR: pH/ORP measurement | Lara PR 2 L/h 10 Bar $728.41 |
Lara PR 5 L/h 7 Bar $728.41 |
Lara PR 10 L/h 5 Bar $803.26 |
Lara PR 2 L/h 20 Bar $836.78 |
On the 2 L/h 20 bar capacity, the discharge connection is 4×7 mm and a head assembly with automatic air bleed is available as an option. Series details are on the AnTech Lara series page.
Optima and Nano series (230 V AC, analogue)
| Model | Flow · pressure | Strokes/min · volume per stroke | Power · weight | Price (excl. VAT) |
|---|---|---|---|---|
| Optima A 5 L/h 10 Bar (Viton O-ring) | 5 L/h · 10 bar | 120 · 0.694 ml | 20 W · 2.16 kg | $290.47 |
| Optima A 5 L/h 10 Bar – Teflon O-Ring | 5 L/h · 10 bar | 120 · 0.694 ml | 20 W · 2.16 kg | $354.15 |
| Optima A 2.5 L/h 15 Bar (Viton O-ring) | 2.5 L/h · 15 bar | 150 · 0.278 ml | 20 W · 2.16 kg | $290.47 |
| Optima A 2.5 L/h 15 Bar – Teflon O-Ring | 2.5 L/h · 15 bar | 150 · 0.278 ml | 20 W · 2.16 kg | $354.15 |
| Nano A 2 L/h 10 Bar | 2 L/h · 10 bar | 180 · 0.185 ml | 10 W · 1.76 kg | $258.07 |
| Nano A 5 L/h 5 Bar | 5 L/h · 5 bar | 180 · 0.463 ml | 10 W · 1.76 kg | $258.07 |
The Optima comes with two O-ring options: Viton is the standard version, and the Teflon (PTFE) version is for chemicals for which Viton is not recommended. The Nano is the lightest and lowest-consumption model among AnTech electromagnetic pumps. Details are on the AnTech Optima series and AnTech Nano series pages; current prices for all models in a single list are on our chlorine dosing pump prices page.
Flow Rate vs Back Pressure: Nova and Optima Models
The flow delivered by an electromagnetic pump increases as the back pressure in the discharge line falls. The AnTech catalogue gives these values in detail for the Nova and Optima series; the Nova values apply to the A, D, DMPR and DMİA models of the same capacity.
| Model | At max. pressure | Intermediate value | Intermediate value | At lowest pressure |
|---|---|---|---|---|
| Nova 3.5 L/h | 20 bar → 3.5 L/h | 16 bar → 4 L/h | 10 bar → 5 L/h | 2 bar → 8.5 L/h |
| Nova 10 L/h | 10 bar → 10 L/h | 8 bar → 13 L/h | 5 bar → 15 L/h | 2 bar → 20 L/h |
| Nova 25 L/h | 5 bar → 25 L/h | 3 bar → 30 L/h | 1 bar → 40 L/h | 0.1 bar → 55 L/h |
| Optima 2.5 L/h | 15 bar → 2.5 L/h | 10 bar → 3 L/h | 6 bar → 4 L/h | 1 bar → 8 L/h |
| Optima 5 L/h | 10 bar → 5 L/h | 6 bar → 6 L/h | 3 bar → 7.5 L/h | 1 bar → 10 L/h |
For example, at a tank inlet with 3 bar pressure, the Optima 5 L/h delivers up to 7.5 litres per hour and the Nova 25 L/h up to 30 litres. For the Lara and Nano series the catalogue gives only nominal flow and pressure; with these models we recommend measuring the flow at low pressure after installation.
Which Model Suits Which Application?
Model selection is determined by the application’s flow rate, line pressure and control requirements. The table is a starting point; carry out a capacity calculation before making a final choice.
| Application | Recommended model | Why |
|---|---|---|
| Well water for a home, villa or workplace, constant flow | Nano A 2 L/h, Lara A 2 L/h | Low flow, simple analogue operation |
| Well or storage tank, tank level monitoring | Lara APS, Nova A | Tank monitoring with a level sensor, fine adjustment step |
| Dosing the chemical at specific times | Lara DS | Operation to a time programme |
| Mains or well line with varying flow | Lara DMS, Nova D | Proportional dosing based on the water meter |
| Line pressure above 10 bar | Nova 3.5 L/h 20 bar, Lara 2 L/h 20 bar, Optima 2.5 L/h 15 bar | High back pressure rating |
| Line with varying pressure or atmospheric tank | Optima A, Nova | Flow–pressure values given in the catalogue |
| Swimming pool, chlorine and pH control | Lara PR, Nova DMPR (separate pumps for chlorine and pH) | Automatic dosing based on ORP and pH measurement |
| Drinking water tank, constant free chlorine | Nova DMİA | Direct measurement of free chlorine |
| Plant automation, remote monitoring | Nova D, DMPR, DMİA | ModBus RTU (RS485) module; 4–20 mA measurement output on DMPR and DMİA |
| Municipal or industrial plant, high flow | EMD-M series | 50–630 L/h, motor-driven mechanical diaphragm |
| Gas-forming chemical, low pressure | Aspendose DMS or PR | Peristaltic design, very low flow setting |
For selection by volume in pools, see our pool chlorine dosing pump page, and for a criteria-based comparison of five AnTech models, see our guide on choosing a chlorine dosing pump.
Mechanical Diaphragm and Peristaltic Series: EMD and Aspendose
Alongside the electromagnetic series, the AnTech catalogue includes the mechanical diaphragm EMD series for high flow rates, and the peristaltic Aspendose series for gas-forming chemicals and very low flow rates. The values below are taken from the catalogue.
EMD-P and EMD-M (mechanical diaphragm)
The EMD-P has a plastic housing and the EMD-M a metal housing. On both, capacity is adjusted manually from 0–100% while running or stopped, and can be controlled with a motor drive that accepts a 4–20 mA signal input.
| Series | Models (flow at 50 Hz) | Max. pressure | Motor power | Head options |
|---|---|---|---|---|
| EMD-P | 14, 32 and 49 L/h | 5 bar | 0.09 kW | PP, PVC, PVDF, stainless steel (SS316) |
| EMD-M | 50, 100 and 150 L/h | 7 bar | 0.25 kW | PP, PVC, PVDF, stainless steel (SS316) |
| EMD-M | 200 and 310 L/h | 5 bar | 0.37 kW | PVC, PVDF |
| EMD-M | 420 and 630 L/h | 3 bar | 0.37 kW | PVC, PVDF |
On a 60 Hz supply the flow rate is higher; for example, the EMD-M 100 L/h model delivers 120 L/h at 60 Hz. Depending on the head option, the balls are ceramic, Pyrex or stainless steel. PVC or PVDF heads are common for sodium hypochlorite; a stainless steel head is not recommended for hypochlorite.
Aspendose (peristaltic)
In the Aspendose series the chemical passes only through the hose, and the wear part is the hose. The upper limits stated in the catalogue are 16% sodium hypochlorite for chlorine and 40% sulphuric acid for pH.
| Model | Flow range | Max. pressure | Control | Power supply |
|---|---|---|---|---|
| Aspendose A (pH–chlorine version) | 0.7–5.1 L/h or 0.5–2.8 L/h | 0.5 bar or 3 bar | Analogue, adjustable flow, rapid button | 95–260 V AC, 3.5 W |
| Aspendose DMS | 0.001–4.3 L/h or 0.001–2.5 L/h | 0.5 bar or 3 bar | Digital, level control, volumetric with water meter, 4–20 mA input | AC 100–240 V or DC 12–28 V |
| Aspendose PR | 0.001–4.3 L/h or 0.001–2.5 L/h | 0.5 bar or 3 bar | As DMS, plus pH or ORP measurement | AC 100–240 V or DC 12–28 V |
On the DMS and PR models, pump capacity is shown on the display in ml/h and flow calibration can be carried out; these two models weigh 0.825 kg and are rated IPX5. Because its back pressure rating is low, the Aspendose is suitable for dosing into open tanks and low-pressure lines. For questions about the EMD and Aspendose series, write to us.
Sources
- AnTech 2025 Product Catalogue (KT_25 R02): technical specification tables, flow–pressure values and material code tables for the Nova, Lara, Optima, Nano, EMD-P, EMD-M and Aspendose series.
Frequently Asked Questions
What types of dosing pump are there?
By operating principle there are three types: electromagnetic (solenoid) diaphragm, mechanical (motor-driven) diaphragm and peristaltic. Electromagnetic pumps are used for small and medium flow rates, mechanical pumps for high flow rates of hundreds of litres per hour, and peristaltic pumps for gas-forming chemicals and low pressure.
Which dosing pump model is suitable for chlorine dosing?
If the flow rate is constant, an analogue model (Lara A, Optima A, Nano A) is suitable; if the flow rate varies, a volumetric model with water meter input (Lara DMS, Nova D); and if the chlorine demand varies, a measurement-controlled model (Lara PR, Nova DMPR or Nova DMİA).
What is the difference between an analogue and a digital dosing pump?
On an analogue pump the flow rate is set manually with the adjustment knob on the front panel; there is no display or programme. On a digital pump the flow rate is entered numerically on the display, and functions such as a time programme, operation by water meter or 4–20 mA signal, password protection and alarms are available.
What is the difference between a pH/ORP model and a free chlorine model?
pH/ORP models (Lara PR, Nova DMPR) adjust chlorine dosing via ORP, the oxidising power of the water; ORP is also affected by pH. The Nova DMİA with free chlorine measurement measures the amount of chlorine directly in mg/L with an amperometric sensor. Direct measurement gives clearer information, but the sensor costs more.
What is the difference between the Nova and Lara series?
The Nova adapts automatically to 95–260 V AC mains and offers capacities up to 25 L/h and a model with free chlorine measurement; its digital models have a PT100 input and ModBus communication via a module. The Lara is a lighter (2.2 kg) series running on 230 V AC; it comprises 20 models across five control types and four capacities.
My line pressure is above 10 bar. Which model should I choose?
The Nova 3.5 L/h models, which operate up to 20 bar, the 2 L/h 20 bar capacity of all Lara types, or the Optima 2.5 L/h, which operates up to 15 bar, are suitable. Measure the pressure at the injection point; the pump's maximum back pressure must be above this value.
Does the electrode or chlorine sensor come with the pump?
No. pH and ORP electrode sets and free chlorine sensors are separate items in the catalogue and are selected to suit the application. Send us your measuring range and we will determine the right one together.
What is the difference between the Viton and Teflon O-ring versions of the Optima?
The only difference is the O-ring material. Viton is the standard version, widely used with sodium hypochlorite and many acids. The version with Teflon (PTFE) O-rings resists a wider range of chemicals and costs slightly more. If you are unsure, send us the name and concentration of the chemical.