Durognost Special Buffer Solution is a solution designed to buffer highly alkaline water samples, ensuring that analyses can be carried out reliably. For accurate analyses at high pH levels The Durognost Special Buffer Solution is a buffer solution for alkaline water samples. It is used to buffer strongly alkaline water samples (above pH 10) for the determination of total and residual hardness using Durognost and Duroval test kits. The contents of the bottle are sufficient for approx. 200 analyses. The Durognost Special Buffer Solution stabilises highly alkaline water samples and brings the pH value into a range that allows for accurate measurement. What is the buffer solution suitable for? The solution is not suitable for calibrating pH meters or as a general pH standard solution, but is used exclusively for buffering highly alkaline water samples. What is the buffer solution used for? Our buffer solution is used to adjust highly alkaline water samples (often with a pH value above 10) to a defined, lower pH value prior to titration or analysis, and to maintain this value. This is important for accurate measurement results, particularly when determining total and residual hardness, for example using DUROVAL® and DUROGNOST® test kits. Applications of the buffer solution The buffer solution is used wherever highly alkaline conditions would interfere with standard testing procedures. It facilitates accurate measurements by lowering the pH to a measurable range.

The DUROGNOST® I (0–0.1 °dH / 0–2 ppm / 0.2 °F) powder test kit is designed for the rapid colorimetric determination of residual hardness in water. Indicator for determining residual hardness in water Special indicator in powder form for the rapid colorimetric determination of the slightest traces of hardness in the range of 0–0.1 °dH or 0–2 ppm CaCO₃ or 0.2 °f (French hardness). Complete with measuring tubes and dosing spoon. With the Durognost I Powder Limit Test Kit, you can easily determine whether your water exceeds a specific limit value. The kit uses a powdered indicator that reacts when mixed with water. The test kit is suitable if you want to check quickly and without complicated measurements whether water is harder than a specified value. It is not suitable if you require exact numerical values for water hardness. Easy water hardness testing The test kit uses a chemical indicator that changes colour depending on the threshold value reached. This gives you a clear result without the need for any equipment. How do I use the indicator? Dissolve 50 mg (one level measuring spoon) of DUROGNOST I indicator in 10 ml of practically completely softened water. The resulting colours correspond to the following values: Green colour: 0 °dH Grey colour: approx. 0.025 °dH Violet-tinged grey colour: approx. 0.05 °dH Red colour: approx. 0.1 °dH and above

The Durognost SR Threshold Test Kit is a simple set for quickly checking whether water hardness levels fall within the range of 0.25 to 0.5 °dH. Check water hardness quickly Special liquid indicator in a dropper bottle for monitoring residual hardness in softened water, calibrated to the limit values of 0.5 and 0.25 °dH (8.9 and 4.47 ppm). With the Durognost SR kit, you can easily determine whether your water falls within this very soft hardness range. The indicator powder changes colour as soon as the water hardness limit is reached or deviates from it. This gives you a clear result quickly. This set allows for approximately 250 analyses. The kit is only suitable if you wish to check whether the water hardness is very low. If you require exact numerical values, this kit is not suitable. Quick test without laboratory equipment First, rinse the measuring tube with the water sample. Then fill the tube with the water sample up to the 5 ml or 10 ml mark. Add one drop of indicator and mix it thoroughly with the water sample by gently swirling the tube. After approx. 30 seconds, the water sample will change colour. Water sample colour: Green = softened water is fine Red = Regenerate the water softener Please note: When comparing the result with the enclosed table, it is essential to take the selected sample volume (5 ml or 10 ml) into account. Please read the enclosed instructions for use carefully before use.

Durognost SR 0 (0.1/0.05 °dH) Threshold test kit for the rapid determination of residual hardness. Threshold monitoring in the very low hardness range Special liquid indicator in a dropper bottle for monitoring the residual hardness of softened water, calibrated to the limit values of 0.1 and 0.05 °dH (1.79 and 0.89 ppm). Complete with measuring tubes and stoppers. Sufficient for approximately 250 analyses; the required measurement time is approx. 30 seconds. Identification of the hardness range When the indicator comes into contact with the water sample, it changes colour as soon as the specified limit values of 0.1 °dH or 0.05 °dH are reached or exceeded. How should the reagent be used? Please rinse the supplied measuring tube with the water sample. Then fill the measuring tube with the water sample up to the 5 ml or 10 ml mark. Add one drop of indicator and swirl the tube to dissolve it completely in the water sample. After a reaction time of approximately 30 seconds, the water sample will change colour. Water sample changes colour: Green = softened water is fine (within the defined range) Red = Regenerate the water softener Please read the supplied instructions for use before use.

The Durognost SR 1 Limit Value Kit is a simple set for quickly monitoring residual hardness in softened water, calibrated to limit values of 1 and 0.5 °dH. Water hardness limit value test for simple checks Special liquid indicator in a dropper bottle for monitoring residual hardness in softened water, calibrated to the limit values of 1 and 0.5 °dH (17.9 and 8.9 ppm). The kit comes complete with test tubes and stoppers and allows for approx. 250 analyses. The colour change of the indicator shows whether the water sample is within or outside the limit value. How does the test work? First, rinse the measuring tube with the water sample. Then fill it with the water sample up to the 5 ml or 10 ml mark. Add one drop of indicator and mix it thoroughly with the water sample by gently swirling the tube. After about 30 seconds, the water sample will change colour. Water sample colour: Green = softened water is fine Red = regenerate the water softener Please note: When comparing the results with the enclosed table, it is essential to note the sample volume used (5 ml or 10 ml). Please read the enclosed instructions for use carefully before use.

Duroval KS 4.3 – Precise Acid Capacity Titration for Swimming Pool Water Duroval KS 4.3 is a precise titration kit for determining acid capacity up to pH 4.3 in water. It is especially suitable for swimming pools and spas. The titration kit is ideal for routine monitoring of water quality in pools. The pipette is easy to read, and the reagents ensure reliable results. What is included in the Duroval KS 4.3? Measuring tube Calibrated dosing pipette Special connecting stopper 8 ml indicator 50 ml titration solution Reliable Titration for Determining Acid Capacity up to pH 4.3 The Duroval KS 4.3 titration kit allows precise determination of acid capacity up to pH 4.3 and is specially designed for monitoring water quality in pools and spas. Acid capacity is an important parameter for assessing the water’s buffering capacity and for safely adjusting the pH value. With its proven titration method, the kit delivers quick and reliable results, making it ideal for regular use during operation. Advantages of Duroval KS 4.3 for Swimming Pool Water Analysis Duroval KS 4.3 stands out for its ease of use and high measurement reliability. The clearly readable, calibrated dosing pipette enables precise dosing of the titration solution, while the clear color change of the indicator ensures safe evaluation. The compact kit is perfect for routine checks and helps operators maintain stable water quality, dose chemicals correctly, and ensure long-term swimming hygiene. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

DUROVAL 1 Drop = 0.1 °dH – Drop-Count Titration Test for Water Hardness Determination High-resolution drop-count test for the precise determination of low water hardness The DUROVAL water hardness test by Heyl is a precise drop-count titration test for determining total hardness in the low measuring range. The analysis is carried out using complexometric titration, where each drop corresponds exactly to 0.1 °dH. This allows even the smallest changes in water hardness to be detected reliably. The test is specifically designed for applications that require high accuracy at very low water hardness levels. With one test kit, approximately 30 analyses can be performed at an average hardness of 1 °dH. Precise water hardness analysis with DUROVAL using complexometric titration Complexometric titration is a proven and highly accurate method for determining water hardness. With the DUROVAL test, the sample is titrated drop by drop until a clearly defined color change is reached. The number of drops used directly corresponds to the water hardness in °dH. Thanks to the fine resolution of 0.1 °dH per drop, DUROVAL is ideal for control, comparison, and documentation measurements where coarse rapid tests do not provide sufficient accuracy. Why DUROVAL by Heyl is the ideal handheld test for water hardness determination Accurate determination of water hardness is essential for water treatment, industrial processes, laboratory analysis, and quality assurance. Especially with softened, demineralized, or treated water, even small deviations in hardness can be technically relevant and may affect processes, systems, or products. DUROVAL is important because: Very low water hardness levels can be measured precisely Even the smallest changes are reliably detected The method works independently of electronic devices Norm-compliant, reproducible results are achieved The test is ideal for routine checks and documentation Unlike coarse test strips or rapid tests, DUROVAL delivers measurable accuracy that is indispensable for technical and analytical applications. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

Duroval 1 Drop 1.0 °dH – Precise Water Hardness Analysis Drop-by-Drop Titration for 0–1 °dH The Duroval 1 Drop 1.0 °dH titration test enables precise determination of very soft water hardness. This test kit allows fast and accurate measurement of water hardness in soft water samples. Clear color changes ensure reproducible results. Precise Drop-by-Drop Titration for Very Soft Water Samples The Duroval 1 Drop 1.0 °dH test was specifically developed for exact measurement of very low water hardness. It is ideal for analyzing soft and softened water within the range of 0–1 °dH. The drop-by-drop dosing provides fine resolution and high measurement accuracy, which is particularly beneficial for sensitive applications in water treatment. Advantages of the Duroval 1 Drop Test for Water Hardness Measurement The Duroval 1 Drop test delivers fast and reproducible results through clearly visible color changes during titration. This simplifies evaluation and minimizes user errors. The compact test kit is easy to use and suitable for routine checks, commissioning, and mobile on-site measurements. It supports reliable water quality control via manual testing and helps optimize processes and system settings. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

The Duroval 1 Drop 1.0 °dH Drop-Counting Titration Test Kit is a manual titration kit for determining water hardness. Determine water hardness simply by counting drops In this test, a defined amount of water is placed in the measuring vessel and the reagent is added drop by drop until the colour changes. Each drop corresponds to 1 °dH, so water hardness can be determined directly by counting. The kit is suitable for testing domestic water, well water, water in technical systems or water softeners when you need to know quickly how hard the water is. Practical for routine checks The 50 tests are supplied as a single kit without a folding box. This makes the kit space-saving and particularly suitable for regular measurements. It allows for approximately 30 analyses at an average hardness of 10 °dH.

The Duroval 1 Drop = 1 °f Drop-Counting Titration Test is a compact titration kit for the manual determination of water hardness. Each individual drop corresponds exactly to one degree of French hardness. One kit allows for approximately 30 analyses to be carried out, assuming an average hardness of 10 °f. Precise water hardness determination by drop titration Titration kit for determining water hardness by complexometric titration. One drop corresponds to one degree of French hardness. The Duroval titration kit was developed for classic titration measurement, in which a reagent solution is added drop by drop to the water sample until a colour change becomes visible. The number of drops directly indicates the degree of hardness in French degrees and allows for simple evaluation without complex measurement technology. Practical water hardness determination The test is carried out manually. First, a water sample is taken and then Duroval is added drop by drop (titrated) until the endpoint is reached. This method allows the water hardness to be determined without the use of electronic equipment.

Titration kit for the determination of carbonate hardness via complexometric titration 1 drop corresponds to 1 carbonate hardnessAnalyses: approx. 30 (at an average hardness of 10 °KH)   This product is available in following versions:  1 pcs.50 pcs. 

Precise Water Hardness Titration Test DUROVAL 1 Drop = 1 °dH Reliable Determination of Water Hardness by Drop Counting Titration The DUROVAL 1 Drop = 1 °dH Drop Counting Titration Test (50 pieces without folding box) is a titration kit for determining water hardness through complexometric titration. The kit is designed to measure water hardness by counting drops until the color change occurs. Approximately 30 analyses can be performed with one set. Reliable Determination of Water Hardness by Drop Counting Titration The DUROVAL 1 Drop = 1 °dH Drop Counting Titration Test is a proven titration kit for determining water hardness using complexometric titration. Evaluation is simple and reliable by counting the drops until the color change, allowing clear and reproducible measurements. The test kit is ideal for routine checks in water treatment, technical operations, and on-site mobile applications. Advantages of the DUROVAL 1 Drop Test for Hardness Analysis The drop counting test enables quick and user-friendly hardness determination without complex measuring equipment. One set allows approximately 30 analyses, making it an economical solution for regular checks. Clear color changes minimize measurement errors and ensure reliable results. The compact format is especially suitable for service tasks and laboratory environments where a simple, robust, and quickly applicable solution is required. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

Duroval A Test Kit – Precise Water Hardness Measurement Complexometric titration for all common hardness ranges The Duroval A test kit enables precise measurement of water hardness in the range of 0–30 °dH using complexometric titration. The complete set includes a calibrated dosing pipette and is suitable for approximately 100 analyses. The test kit allows accurate hardness determination within about 2 minutes with a precision of 0.5 °dH. Reliable complexometric titration for all standard hardness ranges The Duroval A test kit provides precise and reliable determination of water hardness in the measuring range of 0–30 °dH using the proven method of complexometric titration. It is ideal for the analysis of raw water, process water, and service water. Designed as a complete analysis package, the set includes a calibrated dosing pipette that ensures reproducible dosing and consistent measurement results for up to approximately 100 analyses. Advantages of the Duroval A test kit for water hardness analysis The Duroval A test kit delivers fast and reliable hardness determination in only about 2 minutes with an accuracy of 0.5 °dH. The clearly visible color change during titration simplifies evaluation and minimizes user errors. Thanks to its robust design and easy handling, the test kit is suitable for routine checks, commissioning, and mobile applications in water analysis. It is an ideal solution for users who require a precise manual alternative to automatic measurement systems. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

The Duroval A Test Kit 0–60 °f is a handy test kit for determining water hardness using complexometric titration. Precise determination of water hardness by titration The Duroval A test kit is suitable for determining water hardness across all hardness ranges by means of complexometric titration using a liquid titrant and a dosing pipette precisely calibrated in degrees of hardness. Complete with measuring tubes, liquid indicator, dosing pipette calibrated to 0–60° French hardness and 50 ml of titration solution. This test kit allows water hardness to be determined quickly. The kit provides approximately 100 analyses at an average hardness of 26.7 °f, with a measurement time of approx. 2 minutes and a measurement accuracy of 1 °f hardness. Use and special features of the test kit The test kit is particularly suitable for users who wish to determine water hardness values quickly without the need for technical equipment. It is a kit for chemical analysis that is straightforward to use.

The Duroval AF Test Kit 0–60 °f is a compact titration kit for determining water hardness in the range of 0 to 60 °f using a powdered indicator. Measuring water hardness with the test kit Kit for determining water hardness across all hardness ranges via complexometric titration using a liquid titrant and a dosing pipette precisely calibrated in degrees of hardness. Complete with measuring tubes, powdered indicator, dosing pipette calibrated to 0–60° French hardness and 50 ml of titrant. Tests: approx. 100 (at an average hardness of 26.7 °f) Measurement time: approx. 2 minutes Measurement accuracy: 1 °f The Duroval AF test kit determines water hardness quickly and accurately. Everything required for the determination is included in the set. Where can the test kit be used? The test kit is practical because no expensive equipment is required. It can be used at home, in the laboratory or even on the go. How do you use the Duroval AF titration kit? The Duroval method allows for a quick and straightforward determination of the total hardness of water without the need for additional equipment. The indicator turns a deep red in hard water. Adding the titration solution binds the total hardness, causing the colour to change from red to green. The volume of titration solution added with the measuring pipette until the colour change occurs serves as the basis for determining the water hardness. The total hardness of the water sample can then be read directly from the measuring pipette.

The Duroval AP Test Kit 0–30 °dH is a titration test kit for determining water hardness using complexometric titration with a powdered indicator. Precise water hardness analysis with powdered indicator The Duroval AP Test Kit 0–30 °dH is used to determine water hardness in the measuring range from 0 to 30 °dH. The kit contains a measuring tube, a stopper for sealing the measuring tube, a calibrated dosing pipette, a 50 ml titration solution and a powdered indicator. Tests: approx. 100 (at an average hardness of 15 °dH) Measurement time: approx. 2 minutes Measurement accuracy: 0.5 °dH Advantages of the test kit The test kit is easy to use and allows for rapid analysis without the need for electronic equipment. It is ideal for routine checks, service calls or field measurements where manual titration is sufficient. How do I determine water hardness using the Duroval AP titration kit? The Duroval method allows you to determine the total hardness of the water quickly and easily – without any additional equipment. The indicator turns red in hard water. Then add the titration solution: this binds the water hardness and the colour changes from red to green. You can determine the water hardness based on the volume of titration solution added with the measuring pipette until the colour change occurs. The value can then be read directly from the measuring pipette.

Duroval B Test Kit 0–2 °dH – Hardness Determination Reliable titration test kit for precise determination of hardness in very soft or demineralized water by Heyl. The Duroval B Test Kit 0–2 °dH is designed to measure water hardness in very soft or demineralized water samples using titration. With a finely calibrated dosing pipette, liquid indicator, and titration solution, it provides precise and fast measurement. The Duroval B test kit is a complete analysis set for measuring water hardness in very soft or demineralized water. Clear results are obtained within approximately two minutes with an accuracy of 0.05 °dH. Precise titration method for very soft and demineralized water The Duroval B Test Kit 0–2 °dH was specifically developed for accurate measurement of water hardness in very soft or demineralized water samples. Using the proven titration method, even very low hardness levels can be reliably determined, which is particularly important in sensitive water treatment applications. The Heyl test kit includes a finely calibrated dosing pipette, titration solution, and liquid indicator, enabling fast, reproducible, and user-friendly analysis. Advantages of the Duroval B test kit for hardness measurement With the Duroval B test kit, users obtain precise results within about two minutes with a high accuracy of 0.05 °dH. The clearly visible color change simplifies evaluation and minimizes user errors. The complete analysis set is ideal for routine checks, commissioning, and mobile measurements. It provides a reliable manual solution for monitoring very low water hardness and supports safe process and quality control. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

The Duroval BP test kit is a portable analysis kit for measuring water hardness in the low range. It utilises a chemical reaction with a powdered indicator. Convenient test kit for soft water The Duroval BP test kit is a titration kit for determining water hardness via complexometric titration. The Duroval BP test kit is specifically designed to determine the hardness of water with a very low hardness level. Each pack contains: 1 graduated measuring tube 1 stopper for sealing the measuring tube 1 tube of indicator powder with a measuring spoon 1 bottle of titration solution 1 measuring pipette: dosing pipette calibrated 0–2 °dH Tests: approx. 100 (based on an average hardness of 1 °dH) Measurement time: approx. 2 minutes Measurement accuracy: 0.05 °dH How does Duroval BP measure water hardness? The test kit provides clear and reliable results even with very soft water, as the powdered indicator makes the endpoint of the measurement clearly visible. The Duroval method allows for quick and easy determination of the total hardness of the water without the need for additional equipment. The indicator turns bright red in hard water. When the titrant is added, the total hardness is bound, and the colour changes from red to green. The amount of titrant added using the measuring pipette until the colour changes from red to green indicates the hardness of the water sample. The total hardness of the water sample can be read directly from the measuring pipette.

The Duroval C test kit is an analysis kit for determining the carbonate hardness of water samples. It delivers reliable results within a few minutes. Measuring carbonate hardness – a practical solution With the Duroval C test kit, you can determine the carbonate hardness or the m-value (acid capacity up to pH 4.3; KS 4.3) in natural and technical water samples by titration using a liquid titrant and a dosing pipette precisely calibrated in °dH and mmol/l. Complete with measuring tubes, dosing pipette calibrated to 0–20 °dH and 0–7 mmol/l, special connecting stopper, indicator and 50 ml titration solution. This allows for up to approx. 100 analyses to be carried out at an average carbonate hardness of 10 °dH. The measurement time is approx. 2 minutes and the measurement accuracy is 0.5 °dH. How the measurement works Pour the water into the test tube, then add the titration solution drop by drop using the pipette, observing the colour change as you do so. Once the chemical endpoint is reached, you can read the carbonate hardness value in °dH or mmol/l.

DUROVAL Chloride Test Kit for determining the chloride content in water. Complete with all reagents and accessories. Suitable for approx. 200 analyses. The Duroval Chloride Test Kit is a complete measurement system for determining the chloride content in water. The kit contains all necessary reagents, accessories and a calibrated pipette. Within approx. 2 minutes, the kit shows how much chloride is present in your water sample. Simple chloride measurement – quick and reliable The supplied calibrated titration pipette is calibrated for a range of 0 to 300 mg/l chloride and, together with the reagents, enables accurate measurement with a resolution of 10 mg/l Cl⁻. This product is classified as a hazardous substance. Please refer to the safety data sheet. Combine the sample and reagent, add drops using the pipette and identify the endpoint by the colour change. Suitable for: • Measuring the chloride content in natural or industrial water samples • Applications requiring simple, convenient measurement without the need for a laboratory Not suitable for: • Measurements without a complete test kit • Rapid tests without chemical titration • Applications outside the measurement range Why is chloride measurement important? (h3) Chloride is highly corrosive to metals in water and can therefore damage pipes, heat exchangers, boilers and membranes. Regular monitoring ensures that specified limit values in heating, cooling, boiler and water treatment systems are adhered to and that the system operates reliably. Product features: (h3) Analyses: approx. 200 Measurement time: approx. 2 minutes Titration pipette: calibrated 0–30 mg/l Cl⁻ Measurement accuracy: 10 mg/l Cl⁻

Duroval CO₂ Test Kit by Heyl – CO₂ Measurement Made Easy Quick Determination of Dissolved CO₂ The Duroval CO₂ test kit is designed for determining dissolved carbon dioxide in water samples. With this kit, you can reliably measure free carbonic acid in water using drop titration. Quick and Reliable Determination of Dissolved CO₂ in Water The Duroval CO₂ test kit enables precise measurement of dissolved carbon dioxide (free carbonic acid) in water samples. Using the proven drop titration method, CO₂ levels can be determined quickly, easily, and reproducibly. The kit is ideal for applications in water treatment, drinking water monitoring, industry, and technical operations where CO₂ content directly affects water chemistry and material durability. Why Measuring Carbon Dioxide (CO₂) in Water is Important Dissolved carbon dioxide significantly affects the pH, corrosiveness, and chemical stability of water. Excess CO₂ can cause corrosion in pipes, fittings, and system components, especially metallic materials. Additionally, CO₂ plays a key role in the lime-carbonic acid equilibrium. Imbalances can promote both scaling (lime deposits) and material degradation. Regular measurement of free CO₂ allows for targeted water treatment, optimized dosing, and prevention of system damage. The Duroval CO₂ test kit therefore supports safe process management, stable water quality, and long-term protection of water-carrying systems. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

DUROVAL® CPM Test Kit – Quickly Determine Carbonate Hardness & Acid Capacity Set for determining carbonate hardness, p-value, and m-value. The Duroval CPM Test Kit is designed to measure carbonate hardness (m-value; acid capacity up to pH 4.3; Ks 4.3) and p-value (acid capacity up to pH 8.2; Ks 8.2). The kit provides precise results within minutes and enables straightforward analysis. Contents of the DUROVAL® CPM Test Kit Measuring tubes Calibrated dosing pipette 0–20 °dH and 0–7 mmoI/I Special connection stopper Indicators for p-value and m-value 50 ml titration solution Precise determination of carbonate hardness, p-value, and m-value by titration The DUROVAL® CPM Test Kit is a professional analysis set for determining carbonate hardness and water acid capacity. It allows the measurement of p-value (Ks 8.2) and m-value (Ks 4.3), providing essential parameters for the evaluation of raw, process, and operational water. Using the proven titration method, users obtain fast and reliable results in just a few minutes. The kit is ideal for applications in water treatment, industrial processes, and technical operations. Advantages of the DUROVAL® CPM Test Kit for Water Analysis The DUROVAL® CPM Test Kit excels with easy handling and high measurement accuracy. The calibrated dosing pipette ensures precise titration, while the special indicators provide clear and easily visible color changes. The compact kit is ideal for mobile measurements, service operations, and routine checks. It provides a reliable manual solution to quickly assess carbonate hardness and acid capacity and ensures safe control of water chemistry processes. Frequently asked questions How long do Heyl chemicals last? The shelf life is printed on the label of each product. Upon delivery, the guaranteed shelf life is at least 7 months. Can Heyl reagents also be purchased individually? That depends on the specific item to be ordered. For Testoval products, only the complete refill pack can be ordered. The individual small bottles cannot be reordered separately. For the Duroval test kit, the individual components of the refill pack can also be reordered separately. Can the indicator and titration solution be purchased separately? Yes, this is possible for the Duroval product range. Where can I find the safety data sheet? The safety data sheet can be found directly with the product in our shop or separately in the download area under the relevant heading. How can the chemicals 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 chemicals still be used after the expiry date? No, the chemicals can no longer be used after the expiry date. After the expiry date, accurate measurement results can no longer be guaranteed. How should Heyl chemicals be stored? Section 7 of the safety data sheet contains all relevant information on the storage of chemicals. The recommended storage temperature should be between 15-25°C.

The Duroval KB 8.2 Heating System Feed Water is a titration analysis kit for determining the base capacity up to pH 8.2 (KB 8.2) in water samples, e.g. from heating or technical circuits. It contains all the necessary components – measuring tubes, a calibrated pipette, 8 ml of indicator and 50 ml of titration solution. Fast and precise determination of base capacity The Duroval KB 8.2 Heating System Feed Water Kit is suitable for titrimetric measurement of base capacity in natural and technical water samples. The supplied pipette allows the titration solution to be dispensed precisely. The colour change of the indicator clearly indicates the chemical endpoint. This enables you to obtain reliable results in a short time. Suitable for: Checking and monitoring heating and cooling circuits Technical water sampling in laboratories, industrial plants or building services Service and maintenance operations where base capacity must be checked regularly Not suitable for: Measurements without the complete titration kit Applications outside the KB 8.2 measurement range or without a chemical titration method Why is measuring base capacity important? Base capacity indicates how much acid water can buffer before its pH falls below 8.2. This is a key parameter for the condition of heating and process water. Without these measurements, changes in the water cannot be reliably detected, which can lead to corrosion, deposits or malfunctions.

The DUROVAL® Sulphate Test Kit is a titration kit for determining the sulphate content in water, containing all the necessary reagents and accessories. The Duroval Sulphate SO4 Titration Kit is a complete measurement kit for determining the sulphate content in water. Using the pipette and chemical reagents provided, you can measure the sulphate content of water samples directly on site. Easy-to-use test kit for sulphate in water The supplied titration pipette is calibrated for 0–300 mg/l SO42-. By refilling the titration pipette, the measuring range can be extended to double the concentration, and by diluting the water sample with distilled water, to ten times the concentration. The kit contains everything needed for approx. 30 analyses and provides a measurement accuracy of 10 mg/l SO42- for a standard sample. At a 1:10 dilution, the accuracy is 100 mg/l SO42-. Suitable for: o Direct measurements of sulphate content in water samples o Users without a laboratory o Repeated measurements Not suitable for: o Use without the complete test kit o Measurements outside the extended measurement range o Rapid tests without chemical titration Why is sulphate measurement important? In excessive concentrations, sulphate can impair technical equipment, cause deposits or alter the taste of water. This kit allows you to determine the sulphate content. The colour change during titration clearly indicates the endpoint, making the measurement quick and easy to understand. Product information: Duroval titration kit complete with all reagents and accessories Number of analyses: approx. 30 Titration pipette: calibrated 0–300 mg/l SO₄²⁻ Measurement accuracy: 10 mg/l SO₄²⁻ (When the water sample is diluted in a ratio of 1:10, the measurement accuracy is 100 mg/l SO₄²⁻)