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The importance of silicate measurement in industrial water treatment

Silicate measurement is used to determine the content of dissolved silicon dioxide (SiO₂) or silicate (often as SiO₄⁴⁻ ions) in water.

Silicate measurement in industrial water treatment is essential for the following reasons:

  1. Protection of Boiler Systems and Turbines

    Silicates can deposit as solid deposits (e.g., as silicic acid) on heat-transferring surfaces or in steam turbines at high temperatures and pressures. These deposits:

    • Reduce heat transfer and lead to energy losses
    • Increase the risk of corrosion
    • Can cause mechanical damage, especially in turbines with tight tolerances

  2. Prevention of Glass Formation

    At very high temperatures (e.g., in steam generators), silicates can form glass-like layers that are difficult to remove and require extensive chemical cleaning or removal through mechanical surface treatment.


  3. Quality Requirements in Sensitive Processes

    In the semiconductor, pharmaceutical, or food industries, extremely pure water qualities are required. Even low silicate concentrations can contaminate products or disrupt production processes. Furthermore, deposits can form on instrument surfaces during the processing of medical devices, which must be considered critical in the context of further use.


  4. Early Indicator for Leaks

    An unexpected increase in silicate concentration can indicate leaks or contamination in the water treatment system (e.g., in ion exchangers or reverse osmosis systems). Silicate ions are low-valence ions that are displaced from the resin surface in the presence of higher-valence ions.


  5. Optimization of Treatment Processes

    Silicate measurement effectively supports the monitoring of ion exchangers, especially mixed bed resin systems, and can thus be used as an early indicator for the exhaustion of mixed bed cartridges. Another area of application is monitoring the silicate concentration before EDI to ensure the maximum permissible concentration for the module used.

 

How Does Silicate Measurement Work?

The most common method is based on photometric analysis, specifically on the molybdate reaction:

  1. Reaction with Molybdate: In an acidic environment, silicate reacts with ammonium molybdate to form a yellow silicomolybdic acid.

  2. Reduction (optional): This yellow compound can be further reduced with reducing agents (e.g., ascorbic acid or stannous chloride) to a blue dye (heteropoly blue compound).

  3. Photometric Evaluation: The intensity of the color (yellow or blue, depending on the method) is measured at a specific wavelength (e.g., 410 nm or 815 nm) with a photometer. The intensity is directly proportional to the silicate concentration.

 

What is Silicate Measurement Used for in Industrial Water Treatment?

Silicate measurement is used in industrial water treatment for monitoring in the following application examples:

  • Boiler Feed Water & Steam Generators:
    • Silicate can deposit as a stubborn, glass-like coating on heat exchangers and turbine blades. This leads to restricted heat transport and decreased efficiency of heat exchangers.
    • Even low concentrations (< 20 µg/L) can be problematic at high temperatures and lead to damage to the steam turbine.

  • Reverse Osmosis System:
    • Silicate can block membranes.
    • Monitoring helps prevent fouling and extend membrane life.

  • Cooling Water Systems:
    • To prevent silicate deposits in heat exchangers.

  • Semiconductor and Electronics Industry:
    • Extremely pure water is necessary here (Ultrapure Water). Silicate is a critical parameter that indicates residual contamination.

 

The following are typical applications of silicate measurement by industry sector:

  • Power Plants / Energy Generation
    • Silicate measurement at the condensate outlet or in the feed water.
    • Goal: Avoid deposits on turbine blades or in the boiler.
    • Alarm limits are often at 10–20 ppb (µg/L).

  • Water Works & Desalination Plants
    • Monitoring of raw water and outlet of reverse osmosis systems (RO).
    • Protection of RO membranes from fouling.
    • Typical limit values: < 5 ppm, depending on membrane type.

  • Semiconductor and Electronics Industry
    • Use in ultrapure water production (UPW).
    • Extremely low limit values – often < 5 ppb.
    • Silicate is used as an indirect marker for system defects or inadequate filtration.

 

The following illustrates the application possibilities of silicate measurement in a power plant as an example:

Typical Measuring Points

  • Condensate outlet (after condenser)
    • Early detection of leaks in the heat exchanger or contamination with raw water.
    • Prevents deposits on turbine blades.

  • Feed water after desalination/polisher
    • Verification of the cleaning performance of ion exchangers or membrane systems.
    • Protection of the steam generator from deposits.

  • Demin plant (after mixed bed filter)
    • Control of residual contamination after water treatment.
    • Prevention of membrane damage in downstream systems.

 

Advantages for Power Plant Operation

Advantage

Description

Plant Protection

Prevention of stubborn silicate deposits in boiler and turbine.

Continuous Monitoring

Early detection of breakthroughs or leaks.

Maintenance-friendly

Easy handling and long reagent service life.

High Precision

Accuracy in the lower ppb range possible.

The Testomat 808 SiO₂ offers some specific competitive advantages compared to other silicate online analyzers, especially in industrial environments.

 

Competitive Advantages of the Testomat 808 SiO₂ in Comparison

Category

Advantage of Testomat 808 SiO₂

Distinction from Competitors

Reagent Consumption

Very economical consumption through precise micro-dosing.

Low reagent consumption.

Mechanics & Longevity

Robust, modular design with industrial mechanics – made in Germany.

Proven and durable construction of individual components.

 Maintenance Friendliness

Tool-free change of reagent bottles, easy cleaning and clear construction.

User-friendly regarding service and commissioning.

Low Measuring Range

Measuring ranges from 0.3 – 1.2 mg/L– ideal for boiler feed water and ultrapure water.

Freely scalable measuring range in ten gradations.

Adaptability

Freely configurable measuring cycles (interval), analysis triggering via external signals.

High flexibility through free programming of measuring interval and external analysis triggering.

Interfaces

Analog 4–20 mA output + potential-free alarm contact;

Well integrable into existing control systems, due to transmission of measured values and operating states using firmly defined mA values.

Made in Germany Service

Fast support & spare parts availability through German sales and service network.

Short delivery times.

Compactness

Compact design: can be used wall-mounted.

Space-saving due to compact design compared to some floor-standing units.

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Our products for silicate measurement in industrial water treatment

Testomat 808 SIO2, front view of the measuring device for silicate monitoring, 230 V/50-60 Hz 1–4 bar
Testomat® 808 SIO2
Product number: 100660

€3,969.90*
Testomat® 808 SIO2 Reagent A, 500 ml original container, measuring agent for silicate content
Testomat® 808 SIO2 Reagent A - 500 ml
Product number: 141808

Original Heyl Testomat 808 SiO₂ Reagent A – Reliable Silicate Measurement First reagent for Testomat 808 SiO₂ measurement The Testomat 808 SiO₂ Reagent A is used to measure the silicate content in water (SiO₂) and is one of the two necessary reagents for silicate measurement with the Testomat 808 Silicate system. SiO₂ Reagent A initiates photometric silicate determination in the Testomat® 808 SiO₂. The measurement range is 0.3–1.2 ppm SiO₂. Reagent A is precisely calibrated to the measurement method of the Testomat 808 Silicate and allows reliable silicate measurement in the range of 0.3 to 1.2 ppm SiO₂. It is ideal for use in RO process water treatment, e.g., in clinical environments. Using the original reagent ensures consistently precise results, which are essential for stable process monitoring. Heyl Original Indicator for Silicate Monitoring in RO Process Water Treatment Using original Heyl reagents ensures not only high measurement accuracy but also proper operation of the Testomat 808 SiO₂ and the retention of warranty and guarantee claims. It is ideal for clinical applications where reliable silicate monitoring is critical. For example, in sterilization of medical instruments, silicate monitoring in RO process water plays a key role in protecting and preserving medical devices. Häufige Fragen How long does the indicator/reagent last? The shelf life of an indicator is printed on the product label for each batch. In accordance with our terms and conditions, we deliver with a guaranteed minimum shelf life of 7 months. How much indicator is used per analysis? When it comes to indicator consumption, a distinction must first be made between TH indicators (e.g. TH 2005, 2025, 2050, etc.), which are used for the Testomat ECO, Testomat EVO TH, Testomat 2000 and Testomat Limit LT analysis devices, and the indicators for the Testomat 808 (300 series indicators, e.g. indicators 301, 305, etc.). The indicator consumption per analysis for the TH indicators is directly related to the limit value to be monitored. The higher this is, the higher the indicator consumption. For the Testomat 808 indicators (300 series), consumption is approximately 80 µl per analysis. By entering the operating data (analysis interval, limit value, etc.), the exact consumption or indicator requirement per year can be determined using our indicator consumption calculator: Indicators consumption calculator - Heyl Neomeris What sizes are available for the bottles and is there anything to bear in mind? The indicator is available in both 500 ml and 100 ml bottles. The analyser is delivered with the 500 ml bottle set up and the scope of delivery includes the screw cap with hole and insert for the screw cap of the 500 ml indicator bottle. For operation with 100 ml bottles, the bottle size must be changed to 100 ml in the basic programming and the screw cap with hole and insert for the indicator must also be purchased. For Testomat 808 devices, the conversion kit (item no. 37580) must be purchased for the use of 100 ml indicator bottles, and for Testomat 808 SiO2 devices, the insert with screw cap and suction tube (item no. 37645) and the hose connector ø 3.5 mm (item no. 37643) must be purchased. For all other Heylwelt Testomat devices, please use the conversion kit with item no. 40143. Where can I find the safety data sheet? The safety data sheets can be found in the online shop (www.heylneomeris.shop) under the menu item – Service/Help – Downloads – Safety data sheets. How can the indicator be disposed of? Disposal instructions can be found in section 13 of the safety data sheet. Disposal must be carried out in accordance with official regulations. Can the indicator still be used after the expiry date? The indicator can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. What is the optimum storage temperature for the indicator? Section 7 of the safety data sheet contains all relevant information on storing the indicator. The recommended storage temperature should be between 15-25°C. Device warranty / guarantee Measurement errors when using third-party indicators! The use of third-party indicators can lead to large measurement deviations or measurement errors. Damage caused by foreign particles in the area of the dosing pump, measuring chamber or valves is also possible. The use of third-party indicators will void the warranty! Only use original Heyl indicators, which are specially designed to meet the requirements of the measuring devices and thus guarantee accurate measurement results.

€173.20*
Testomat® 808 SIO2 Reagent B, original container 500 ml, measuring agent for silicate content
Testomat® 808 SIO2 Reagent B - 500ml
Product number: 141809

Original Heyl Testomat 808 SiO₂ Reagent B for Silicate Determination Second reagent for silicate measurement with the Testomat 808 Silicate system The Testomat 808 SiO₂ Reagent B is the second required reagent for photometric measurement of silicate content (SiO₂) in water. SiO₂ Reagent B, together with Reagent A, completes the silicate determination using the Testomat® 808 SiO₂. The measurement range is 0.3–1.2 ppm SiO₂, enabling reliable and reproducible silicate analysis. Reagent B is precisely calibrated to the Testomat 808 Silicate measurement method and allows reliable determination of silicate within the 0.3–1.2 ppm SiO₂ range. Advantages of Using Original Reagent B for Testomat 808 SiO₂ by Heyl Using original Heyl reagents is essential for the proper operation of the Testomat 808 SiO₂ measuring device. It significantly contributes to process reliability, long device lifespan, and the retention of warranty and guarantee claims. Häufige Fragen How long does the indicator/reagent last? The shelf life of an indicator is printed on the product label for each batch. In accordance with our terms and conditions, we deliver with a guaranteed minimum shelf life of 7 months. How much indicator is used per analysis? When it comes to indicator consumption, a distinction must first be made between TH indicators (e.g. TH 2005, 2025, 2050, etc.), which are used for the Testomat ECO, Testomat EVO TH, Testomat 2000 and Testomat Limit LT analysis devices, and the indicators for the Testomat 808 (300 series indicators, e.g. indicators 301, 305, etc.). The indicator consumption per analysis for the TH indicators is directly related to the limit value to be monitored. The higher this is, the higher the indicator consumption. For the Testomat 808 indicators (300 series), consumption is approximately 80 µl per analysis. By entering the operating data (analysis interval, limit value, etc.), the exact consumption or indicator requirement per year can be determined using our indicator consumption calculator: Indicators consumption calculator - Heyl Neomeris What sizes are available for the bottles and is there anything to bear in mind? The indicator is available in both 500 ml and 100 ml bottles. The analyser is delivered with the 500 ml bottle set up and the scope of delivery includes the screw cap with hole and insert for the screw cap of the 500 ml indicator bottle. For operation with 100 ml bottles, the bottle size must be changed to 100 ml in the basic programming and the screw cap with hole and insert for the indicator must also be purchased. For Testomat 808 devices, the conversion kit (item no. 37580) must be purchased for the use of 100 ml indicator bottles, and for Testomat 808 SiO2 devices, the insert with screw cap and suction tube (item no. 37645) and the hose connector ø 3.5 mm (item no. 37643) must be purchased. For all other Heylwelt Testomat devices, please use the conversion kit with item no. 40143. Where can I find the safety data sheet? The safety data sheets can be found in the online shop (www.heylneomeris.shop) under the menu item – Service/Help – Downloads – Safety data sheets. How can the indicator be disposed of? Disposal instructions can be found in section 13 of the safety data sheet. Disposal must be carried out in accordance with official regulations. Can the indicator still be used after the expiry date? The indicator can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. What is the optimum storage temperature for the indicator? Section 7 of the safety data sheet contains all relevant information on storing the indicator. The recommended storage temperature should be between 15-25°C. Device warranty / guarantee Measurement errors when using third-party indicators! The use of third-party indicators can lead to large measurement deviations or measurement errors. Damage caused by foreign particles in the area of the dosing pump, measuring chamber or valves is also possible. The use of third-party indicators will void the warranty! Only use original Heyl indicators, which are specially designed to meet the requirements of the measuring devices and thus guarantee accurate measurement results.

€164.00*
Testomat® 808 SIO2 reagent kit A+B, two 100 ml bottles, silicate content measurement
Testomat® 808 SIO2 Reagent set, reagents A 100 ml & B 100 ml
Product number: 140808

Original reagent kit from Heyl for measuring silicate in water for use in the Testomat 808 SIO2 – two 100 ml bottles (A+B) for precise SIO2 monitoring. SIO2 reagent kit for Testomat 808 – reagents A+B for silicate measurement Complete A+B reagent set for reliable determination of silicate content The Testomat 808 SIO2 reagent set A+B consists of two original 100 ml bottles of reagents A and B, which have been specially developed for photometric silicate measurement. The kit covers the entire measurement process and is ready for immediate use. Thanks to the coordinated measurement range of 0.3 to 1.2 ppm SIO2, even low silicate concentrations can be reliably detected. Advantages of the original reagent kit for silicate measurement from Heyl With the A+B reagent set, you can use precisely coordinated components for silicate determination in the Testomat 808 SIO2. The reagents are factory calibrated and guarantee consistently reproducible results in the monitoring range from 0.3 to 1.2 ppm SIO2. Application & areas of use Measuring parameter: Silicon dioxide in water – particularly important for pure or deionised water. Measuring range: approx. 0.3–1.2 ppm SIO2 – tailored to the capacity of the Testomat 808 SIO2 system. Package contents: 100 ml each of reagent A and reagent B Areas of application: Monitoring of silicate in deionised water, process water, in clinical sterilisation processes or other technical water systems. Advantages: Original reagents ensure continuously accurate measurements and support the functional integrity of the measuring system.

€92.80*
Connection set for the Testomat 808, plastic hose, reduction from 10 to 6 mm and a shut-off valve
Adapter set for Testomat® 808
Product number: 37610

In this adapter set are all parts included, that you need to install a Testomat® 808.   Connection set consisting of: plastic hose 6/4 x 1.5 m length   reduction 10 t0 6 mm   shutoff 3/8" to 6 mm

€118.10*
Annual service kit Professional Testomat 808 SiO₂ component image with sight glasses, rubber seals, brush set and blue screw-cap inserts with suction tubes
Annual service set professional Testomat® 808 SiO2
Product number: 890611

Contains:  2 x Sight glass windows 30x33 x Flat gasket 24x2 EPDM 601 x Bottle insert for screw cap and push-fit suction tube, 100 ml bottle1 x Bottle insert for screw cap and push-fit suction tube, 500 ml bottle1 x brushes set

€176.20*
Service set professional for 2 years of maintenance Testomat 808 SiO₂, overview of all components such as viewing windows, seals, brushes, etc.
Service set Professional for 2-year maintenance Testomat® 808 SiO2
Product number: 890612

Service set contains:2 x sight glasses 30 x 33 x flat gasket 24 x 21 x insert for screw cap & suction tube 100 ml bottle1 x insert for screw cap & suction tube 500 ml bottle1 x double pump head conversion kit1 x gear motor2 x Hose connector1 x Cleaning brush set Important: After replacement, the pump must be recalibrated in Testomat® 808 SiO2.The adjustment is available from firmware version T808_83-003. Carry out a firmware update for older versions before performing the adjustment! (Serial number less than 253.061)For this calibration, it is important that you use water with a silicate content of 0 ppm, otherwise the zero point calibration will be incorrect and lead to false measurement results.To ensure this, please use the silicate filter cartridge specially developed for this process for the T808 SiO2, article 270344.(For additional information and instructions on the equipment you need for the software update, please refer to the operating instructions. The instructions "Replacing the pump head on Testomat® 808 SiO2" are also available)

€1,148.20*
Double pump head for Testomat 808 SIO2, with screws, shaft extension, spacer plate, double pump head with hoses, hose extension and an Allen key
Double pump head for Testomat® 808 SiO2
Product number: 40395
Replacement of: 37801 und 37859

ID=1.6mm complete2x screws M3x40, M3x501x shaft extension1x spacer plate1x double pump head with hoses1x hose extension1x 1.5 mm Allen keyImportant:After replacement, the pump must be recalibrated in Testomat® 808 SiO2. The adjustment is available from firmware version T808_83-003. Update the firmware of older versions before carrying out the adjustment! (serial numbers lower 253.061)It is important to use water with a silicate content of 0 ppm for this adjustment, otherwise the adjustment of the zero point is faulty and leads to incorrect measurement results. To ensure this, please use the silicate filter cartridge for the T808 SiO2, article 270344, specially developed for this process.(For additional information and notes on the equipment required for the software update, see the operating instructions as well as the "Replacing the pump head in Testomat808 SiO2" document)

€792.30*
Silicate filter cartridge T808 SiO2, side view of filter housing with special resin, compact cartridge for pump head adjustment
Silicate filter cartridge T808 SiO2 for changing the double pump head
Product number: 270344

Dear customers, please note that the calibration of the Testomat® 808 SiO2 can only be carried out with silicate-free water. Therefore, please use the silicate filter cartridge specially developed for this purpose when replacing the double pump head (art. no. 40395) and the associated pump adjustment.The cartridge filled with the special resin is inserted into the sampling line of the unit before the inlet and removed again after the adjustment. The pump replacement instructions describe the use of the silicate filter, storage conditions and shelf life. After the first use, the filter can be used up to 10 times within one year for balancing. After one year, the filter must be disposed of.

€184.80*