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Frequently Asked Questions

Accuracy Custom Tests Range Standards
Alkalinity Definitions REACH Compliance Titret usage
Applications Dilutions Sample colour Unit Conversions
COD Disposal Sample pH USEPA Acceptance
Colour Development Time Instructions & SDS Sample Volume Warranty
Colour Match Instrument Calibration Shelf Life
Competition Instrument Compatibility Shipping Regulations
Commodity Codes No. of Tests / Kit Soil Analysis


Q) What is the accuracy of the CHEMetrics test kits?

A) The accuracy of CHEMets®, ULR CHEMets® and VACUettes® test kits is ±1 colour standard increment. The MDL of visual test kits is the lowest concentration at which developed colour can be visually distinguised, and is equal to the concentration of the first comparator increment.

The accuracy of the Titrets® test kits varies with the analyte concentration because the Titret® ampoules have a non-linear scale. At twice the minimum concentration for a particular kit range, with the exception of the Carbon Dioxide Titret® kit catalogue No. K-1910, the accuracy is ±10% error. For K-1910, the accuracy is ±30% at twice the minimum concentration.

Accuracy information for Instrumental Test Kits - Vacu-vials® Test Kits and COD vials - can be found on the relevant individual analyte product page on this web site. For Vacu-vials test kits, the pdf file can be downloaded by clicking on the range field of the test kit in the yellow table. For COD vials, the accuracy pdf file is listed at the bottom of the page, which applies to all COD Test Kits.

Galgo can provide a Certificate of Conformance that certifies the analytical performance of any CHEMetrics water analysis product.

To request accuracy information for any of our CHEMetrics® Instrumental Test Kits, or to request a Certificate of Conformance, please contact us at Galgo.

For information on verifying the accuracy of CHEMetrics photometers in the lab or field, please see the Photometer Verification Kits page.

Manual sample dilution will lower the sensitivity of CHEMetrics test kits, however it may be necessary if the sample is too concentrated or discoloured. Please see the Dilution section below for more information.


Q) Is it possible to meausure the P Alkalinity of a sample with a CHEMetrics Alkalinity test kit?

A) Yes, the CHEMetrics Hydrate Alkalinity Test K-4710 allows the analyst to measure either the Hydrate Alkalinity or the Phenolphthalein (P) Alkalinity. Please see the Alkalinity page for more information.

Q) Is it possible to determine the relative concentrations of CO3= and HCO3- Alkalinity

A) Yes, this can be determined by measuring the T and P Alkalinity of the sample using CHEMetrics test kits and the relevant equation. Please see the Alkalinity page for more information.


Q) What parameters do I need to test for in my specific industry?

A) The required testing parameters vary widely within specific industries. However, CHEMetrics has identified the most often tested parameters in several major industries. Please see the Industries and Applications page for more information.

Q) Will CHEMetrics develop or customise a test kit for my specific application?

A) New CHEMetrics products often originate directly from customer requests for streamlined testing methods. To be considered for a custom product, the test should be run frequently, or it should be a procedure that is performed widely in the industry. Please contact us for more information regarding customised kits or chemistries.


Q) When can I use the mercury-free COD test kits? Are the mercury-free reagents USEPA approved?

A) The mercury-free reagent is designed for use with samples that contain low levels of chloride. If your sample has less than approximately 100 ppm of chloride (less than approximately 1000 ppm for 0-15,000 ppm test range), the mercury-free test is applicable. If your samples contain higher concentrations of chloride, the mercury-containing test is required. The mercury-free reagents are not approved by the USEPA for reporting purposes in the USA.

Q) I compared my COD test results to (Competitor) and they did not correspond.

A) If comparing product from two vendors, keep in mind that the accuracy of ALL COD vials commercially available is ± 5%. Therefore, a difference of as much as 10% could result when comparing various product sources. For this reason CHEMetrics highly recommends that comparison data be generated with COD Standard solutions.

Data generated using COD standard solutions are dependable and should remove any bias associated with the comparative analyses of samples. In addition, ALL COD vials, commercially available, can produce varying test results if the instrumentation is not zeroed correctly. It is imperative that when zeroing the instrument, the reagent blank is from the same manufacturing lot. For example, if running Hach® vials and CHEMetrics® vials, it would be necessary to run a blank from the CHEMetrics® lot and a blank from the Hach® lot. The instrument would have to be re-zeroed when switching between lots (or vendors).

Please see the COD Procedure Notes document for more information.

COD Comparison Notes - comparing CHEMetrics Vials to alternative suppliers

Q) Can I use CHEMetrics COD vials in my Hach® instrument?

A) Because CHEMetrics® COD kits are equivalent to Hach's, any instrument that can accept Hach's 16 mm COD vials (Reactor Digestion method) can accept CHEMetrics COD vials. Furthermore, CHEMetrics vials may be used with Hach’s factory-programmed COD calibrations (No endorsement by Hach Company is implied or intended).

Hach Instruments that work with CHEMetrics COD Reagent Vials

Note: LED photometers do not produce accuracy and precision equivalent to that attainable with spectrophotometers. The use of LED instrumentation is not recommended for COD measurements which will be used for NPDES reporting in the USA.

Colour Development Time

Q) How important is the colour development time allotment listed in the test procedures?

A) Timing is very important in colourimetric (colorimetric) chemistries. Some chemistries will continue to develop colour after the specified analysis time. The most accurate test results will be obtained when the reading is taken at the time prescribed in the instructions. Visual or instrumental readout after an extended period can give an erroneous result.

Colour Match

Q) The colour match between my test ampoule and the colour standards is poor. Why?

A) This condition may be influenced by the light source, background colour of the sample and/or a chemical interference. To obtain the best colour match, the light source should be fluorescent. The sample background colour issue is addressed under the “Sample Colour” heading. If a chemical interference is suspected, see the “Dilutions” heading or contact CHEMetrics' Technical Service department for assistance.

Commodity Codes

Q) What are the commodity codes for CHEMetrics products for international shipping?

A) Commodity codes and Export Control Classification Numbers for CHEMetrics products are as follows.

Catalogue No. Description Commodity Code ECCN
A-xxxx* Accessories 3822.00.0002 EAR99
A-7320 COD Photometer (Low Range) 9027.80.3100 3A99
A-7325 COD Photometer (High Range) 9027.80.3100 3A99
C-xxxx Comparator 3822.00.0002 EAR99
I-xxxx* SAM Photometer 9027.80.3100 3A99
I-0003 SAM Verification Kit 3822.00.0002 EAR99
I-5543 Peroxide Verification Kit 3822.00.0002 EAR99
I-7433 Ozone Verification Kit 3822.00.0002 EAR99
K-xxxx Test Kit 3822.00.0002 EAR99
R-xxxx Refill 3822.00.0002 EAR99
V-0002 V-2000 Verification Kit 3822.00.0002 EAR99
V-2000 Multi-Analyte Photometer 9027.80.3100 3A99
V-3000 Multi-Analyte Photometer 9027.80.3100 3A99

* With the exceptions listed


Q) How do CHEMetrics products compare to Hach and other traditional style analysis products?

A) Those products typically use similar chemistries but customers who have used both often report that CHEMetrics vacuum sealed liquid reagent ampoules are faster (less mixing and measuring), safer (limited exposure to chemicals), and easier to use (less chance of operator error). These three factors add up to an overall savings in time and money.

Please see the Product Comparisons & Evaluations page for more information.


Q) How does ppm correspond to mg/l?

A) Most CHEMetrics kits report results as ppm, which is equivalent to mg/l for water samples.

Other helpful conversions:

1% = 10,000 ppm
1 ppm = 1000 ppb

Q) How can I express nitrate results as NO3, instead of NO3-N? Phosphate results as PO4-P instead of PO4?

A) To convert nitrate results from NO3-N to NO3, the results must be multiplied by 4.43.

To convert phosphate results from PO4 to PO4-P, the results must be divided by 3.1.


Q) I routinely test for (your analyte) using a method that could be made faster, easier and safer with a self-filling ampoule. Will CHEMetrics develop a custom test kit for me?

A) If you've ever laboured through a lab procedure, longing for a time-saving, self-filling ampoule method, call us! Our products often originate directly from customers eager for easier, more efficient ways to perform routine determinations. To be considered for a custom product, the test should be one that you perform frequently, or one that is widely used throughout your industry.

CHEMetrics have extensive experience with private-label packaging and service. and are very flexible in working with each customer's special needs, from printing labels to custom packaging. For more information on custom products and private labeling, please contact us at Galgo. We look forward to building a test that works for you.


Q) What are CHEMets Kits? Vacu-vials Kits? VACUettes Kits? Titrets Kits?

A) Each of these CHEMetrics testing systems is based on the self-filling ampoule--a glass ampoule with liquid reagent vacuum-sealed inside. Sample is automatically drawn into the ampoule and mixed with reagent when the ampoule's tip is broken below the surface of the sample. The four variations of this technology are as follows:

CHEMets Kits - designed for visual analysis of samples with low to medium analyte concentration. Quantitation is performed by visual colour comparison with liquid colour standards.

Vacu-vials Kits - designed for instrumental analysis of samples. Quantitation is performed photometrically or spectrophotometrically.

VACUettes Kits - designed for visual analysis of samples with high analyte concentration. Auto dilution feature on ampoule tip eliminates the need to perform manual dilutions of concentrated samples. Quantitation is performed by visual colour comparison with liquid colour standards.

Titrets Kits - designed for titrimetric analysis of samples. A valve assembly attached to the ampoule tip allows the analyst to draw small amounts of sample into the ampoule until a colour change indicates the equivalence point of the titration. Quantitation is performed by reading the scale off the graduated ampoule.

Please see the Patented Test Methods page for more information.


Q) Can I dilute my sample? What can I do if my developed sample colour is darker than the darkest colour standard?

A) In many cases, we can recommend dilution when a sample is slightly coloured or turbid, when interferences are expected or when analyte concentration is high. However, sample dilution will reduce the sensitivity of your test kit and is not appropriate for all analytes, for instance, alkalinity, carbon dioxide, conductivity, dissolved oxygen, pH and ozone.

We recommend using distilled or deionised water to perform the sample dilutions. A 1:1 dilution (2× dilution: 1 part sample to 1 part distilled/deionised water) will double the range of your test kit. Higher dilutions can also be performed. Be sure to multiply your results to compensate for the dilution. For example, with a 1:2 dilution (3× dilution) it would be necessary to multiply the result by 3.

High range Chlorine and Nitrate CHEMets test kits employ a dilution step as part of the test procedure and come complete with the required MiniPet® and dilution tips. The MiniPet® is reusable. Each refill pack comes with 30 ampoules and 30 dilution tips. MiniPets® and dilution tips can be purchased separately for use with other kits. CHEMetrics also offers a Sample Dilution Kit, catalogue no. A-0188 for convenient dilutions between x10 and x5000. Please see the Dilution Kit page for more information on the use of MiniPets®.

Q) Will dilution affect the accuracy of my test result?

A) The accuracy of the test kit will not change but if the original sample has been diluted then the accuracy of the final test result will decrease by the factor of dilution, assuming that the manual dilution procedure has been followed correctly and not introduced errors. We therefore recommend to use the most appropriate test kit for the purpose to minimise the amount of dilution required for your samples to provide the greatest level of accuracy, after factors such as discolouration, turbidity and/or interferences have been taken into consideration.

For instance, the Chlorine Dioxide CHEMets kit K-2705 has an accuracy in standard use of ±1 increment, i.e. ±1 ppm throughout the majority of the flat (high range) comparator range. However, with an original sample concentration of 70 ppm, and a 10× dilution (1 part sample to 9 parts distilled water) prior to testing, then the accuracy of the result for the original sample will be ±10 ppm of original sample concentration.

To provide an example of a Vacu-vials photometric test kit, Ammonia K-1503, the accuracy around 5.25 ppm is ±0.53 ppm using the standard test procedure and using a V-2000, V-3000 or Spectrophotometer. However, with an original sample of around 50 ppm concentration, employing a 10× manual sample dilution (1 part sample to 9 parts distilled water), the accuracy of the test result for the original sample becomes ±5.3 ppm.

Other options include sample filtration remove excess colour or turbidity that is not related to the actual sample analyte concentration. However, this may not always be appropriate depending on the testing environment or the analyte being measured. Another option is to use a photometric test kit rather than a visual test kit, in combination with a Sample Zeroing Accessory Pack (SZAP) to zero the instrument with the sample prior to measurement.

Turbidity and turbidity interference in colourimetric water analysis are discussed on the Turbidity Interference page.


Q) How do I dispose of used reagent ampoules?

A) CHEMetrics' Safety Data Sheets (SDS) clearly list the chemical components of the solutions and reagents in our test kits. The operator must comply with local, county and nationwide regulations for waste disposal. Contact your local regulatory agency or waste disposal company to learn the specific regulations governing your area. Please see the Links page for contact details. Galgo also offers a disposal service, please contact us for a quotation.

Instructions & Safety Data Sheet (SDS)

Q) How do I obtain current instructions for a CHEMetrics test kit?

A) Test Instructions for all kits and instruments are available for download on this web site. Click on the test kit catalogue number in the table on the relevant parameter pagea>. You may also contact us if you wish to request hard copies. Please provide us with the catalogue number of the kit and your fax number or mailing address.

Q) How can I obtain a Safety Data Sheet (SDS) for a CHEMetrics product?

A) SDSs in digital (pdf) format can be downloaded from the SDS page in the Support section of this site. If you need assistance, please contact us.

Instrument Calibration

Q) How can I check the calibration of my instrument?

A) The calibration can be checked by analysing a standard solution of known concentration. We recommend testing at 25% and 75% of full range. We offer a range of verification kits for the V-2000 and SAM photometers using NIST traceable standards. We also presently offer a limited range of standard solutions, for Chemical Oxygen Demand and Hydrogen Peroxide.

Q) How do I generate an instrument specific calibration curve?

A) To generate an instrument specific curve it will be necessary to prepare and analyze five standard solutions in the same matrix as your sample. The standard solutions should encompass the range of the test kit and should include a blank. The absorbance of each of the five standard solutions is plotted against the concentration. We can arrange for CHEMetrics to generate a calibration equation from your data.

Instrument Compatibility

Q) Can I use CHEMetrics ampoules in my spectrophotometer?

A) Yes, CHEMetrics products can be used in many instruments other than our preprogrammed instruments. Most spectrophotometers capable of accepting a 13 mm (1/2 inch) diameter cell can be used with Vacu-vials ampoules. CHEMetrics VACU-vials kits include a calibration equation for use with spectrophotometers. An excellent way to validate your spectrophotometer with CHEMetrics Vacu-vials ampoules is to analyze standards of known concentration when possible.

Number of Tests per Kit & Reordering Accessory Solutions

Q) How many tests can I perform with one test kit?

A) In most cases, 30 tests can be performed with each CHEMetrics kit. Detergents, filming (aliphatic) amines, and FoalWatch® kits contain 20 tests. Sulphite in wine kits contain 10 tests. The TPH refill contains 16 tests. COD kits are sold in 25-, 98-, and/or 150-count kits. Most ampoule refill packs contain the same number of tests as the kit.

If a particular test procedure requires one or more accessory solutions to be employed in addition to the vacuum sealed ampoule, then 1 bottle of each accessory solution is provided in the test kit. The bottle(s) of accessory solution which are provided will allow for 30 to 90 tests to be performed (the equivalent of 1 to 3 ampoule refills). Additional accessory solution may be purchased, if needed. Accessory Solution Packs generally contain 6 additional bottles of a particular accessory solution (enough solution to perform approximately 200 additional tests).


Q) What test range do I need for my application?

A) Because CHEMetrics' test kits are designed for use in a variety of industries, the ideal test range for a particular application may not be known. However, CHEMetrics' Technical Services staff can make a recommendation in many cases.

Q) How is it that some CHEMetrics kits offer 2 ranges (e.g., 0-1 and 1-10 ppm)?

A) A dual range kit contains 2 separate colour comparators (low and high range). When a test is performed, the analyst will use either or both comparators to obtain the test result. No sample dilution or test repetition is required.

Q) What if I need to test outside of the range of CHEMetrics’ test kits?

A) The range of many of CHEMetrics’ test kits can be extended by performing dilutions as discussed under the Dilutions section. For lower range testing see the “Custom tests” section. While the ranges of many of CHEMetrics’ test kits are based on industry demand, some are restricted due to the limitations of the test method or available technology.

REACH Compliance

Q) What is REACH?

A) EU REACH is a European Union regulation concerning the Registration, Evaluation, Authorisation and restriction of Chemicals, EC 1907/2006. The aim of EU REACH is to improve the protection of human health and the environment through superior and earlier identification of the intrinsic properties of chemicals.

Under EU REACH, manufacturers and importers are obliged to register substances they produce or import in quantities over 1 tonne per year with the European Chemicals Agency (ECHA) in Helsinki. The deadline for registration of 'dangerous substances' (produced over 1 tonne per year) was 30 November 2010. The deadline for registering non-dangerous substances of over 1 tonne per year was 31 May 2018.

The EU REACH Regulation was brought into UK law on 1 January 2021 and is known as UK REACH. UK REACH has a similar threshold of 1 tonne per year per chemical to require registration.

Q) Is Galgo registered under REACH?

A) Galgo (UK) Ltd does not import any particular chemical substance (constituent ingredient of a CHEMetrics test kit for example) in quantities of over 1 tonne per year. As a result company was not required to pre-register or register any chemical according to EU REACH. As Galgo (UK) Ltd did not have any EU REACH registrations, it has not been required to transfer anything to UK REACH. Galgo (UK) Ltd is not presently required to make any new registrations with UK REACH. If however, in the future, Galgo does start to import any particular chemical ingredient in quantities over 1 tonne a year, then registration with UK REACH will be necessary (for each relevant chemical), and we will inform our customers accordingly.

Q) What action is required?

A) Neither the downstream (end) user nor any distributor are presently required to do anything under UK REACH with regards to CHEMetrics products.

End users of chemicals must apply the risk management measures for any dangerous substances identified on the manufacturer's Safety Data Sheets (SDS); and should use chemical products safely, responsibly and in accordance with the supplied manufacturer's instructions and recommendations.

End users also have a right to make their use of a substance known to the supplier in order to make it an identified use and have it covered in the supplier’s chemical safety assessment. Alternatively they may conduct their own chemical safety assessment and report this use to the chemicals agency. Neither action is however a mandatory requirement.

Sample Colour

Q) My sample is coloured. Can I use CHEMetrics test kits?

A) Slightly turbid or coloured samples can be analysed using the instrumental test kits. Visual test kits can sometimes be used, especially when analyte concentration approaches the high end of the test range.

Also see the “Dilutions” section above.

Sample pH

Q) In order to use CHEMetrics test kits, what pH does my sample need to be?

A) A general rule of thumb for colourimetric testing is that sample pH should be between 4 and 8.

Sample Volume

Q) How much sample do I need to conduct the test?

A) In most cases we recommend that the user have at least 25 mL of sample for Vacu-vials, CHEMets, ULR CHEMets, and Titrets kits. Smaller volumes are needed for VACUettes kits.

Shelf Life

Q) What is the shelf life of my CHEMetrics product?

A) The CHEMetrics water analysis ampoule product line employs vacuum packaging to ensure the longest possible shelf life. CHEMetrics stated shelf-life is based on products stored in the dark and at room temperature. In other words, the unused ampoules should be kept inside the cardboard refill packaging when not not in use, and kept inside the plastic kit case; or in the case of spare refill packs, kept in a cupboard or similar when not out in the field. The majority of products have a shelf life of at least 2 years. Refrigeration in many cases extends the shelf life.

For a list of products that have (or contain a component that has) a shelf-life of less than one year, please see the table below.

CHEMetrics Product Shelf-Life Bulletin < 1 year

For a list of products that have (or contain a component that has) a shelf-life of at least one year, please see the table below.

CHEMetrics Product Shelf-Life Bulletin > 1 year

Shipping Regulations

Q) Are CHEMetrics products classified as dangerous goods?

A) Certain CHEMetrics test kits, refills and accessory solutions are classified as dangerous goods permissible to be shipped in excepted quantities. A summary of what products are affected and the maximum permitted quantities per carton can be found here.

Soil Analysis

Q) Can I use CHEMetrics kits to analyze soils?

A) All CHEMetrics' test kits are designed specifically for water or other liquid analysis, not soil analysis. However, it is sometimes possible to extract, digest, or distill soil samples for analysis with our kits. Soil analysis test procedures are not currently included with the kits. Please contact us for information on soil analysis methods and references.


Q) Does CHEMetrics offer standard solutions so that I can confirm/document the analytical performance of the test kit?

A) CHEMetrics' own branded Standard Solutions are currently only available for Chemical Oxygen Demand (COD) and Hydrogen Peroxide. Standards can be obtained from a variety of sources, including Fisher Scientific or Labchem. A detergent standard can be obtained from Ricca Chemical Company.

Titret Usage

Q) After drawing the initial aliquot of sample into the Titret ampoule, I am unable to get it to draw any more sample.

A) Titrets ampoules are vacuumed sealed and use the vacuum to draw sample into the ampoule, therefore, if the vacuum is lost, sample will not be drawn into the ampoule. The valve assembly should be firmly seated at the reference line and not removed once the ampoule has been snapped. Also, it is important that pressure be applied to the bead valve ONLY when the valve assembly tip is submerged in the sample.

Q) What if my Titret ampoule fills all the way and I do not see a colour change? What if I see an immediate colour change?

A) Titrets ampoules are based on a "reverse titration". If the ampoule fills completely and the endpoint is not reached (no colour change) then the sample concentration is below the range of the kit. (Not enough analyte was added to reach the equivalence point of the titration and effect a colour change). If an immediate colour change occurs, the sample concentration is above the range of the kit.

USEPA Acceptance

Q) Are CHEMetrics test kits USEPA Accepted for reporting purposes?

A) CHEMetrics chlorine Vacu-vials® test kits (DPD chemistry) and COD vial methods (mercury-containing 0-150 and 0-1500 ppm ranges) are USEPA-accepted and may be used for compliance monitoring in the USA. In most other cases, the test kits are based on USEPA methodologies. Method references are listed in the catalogue, on the web page, and in individual product instructions.


Q) How long is the warranty period of my CHEMetrics product?

A) Galgo (UK) Ltd warrants the CHEMetrics products it supplies to be free of defects in materials and workmanship from two years from the date of manufacture, except as follows. Those reagent products that have shelf lives less than two years are warranted through the expiration dates printed on the merchandise. Instrument products, other than their expendable components, are warranted for one year from receipt by the customer.

This warranty does not apply to merchandise improperly stored or handled by a party other than Galgo or CHEMetrics. This warranty shall be in lieu of all other warranties, express or implied, including any implied warranty of merchantability or fitness for a particular purpose.

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