Tietokeskus

The importance of pH testing in pools

Getting the pH right in your pool or hot tub is critical as it impacts on all the other chemicals you will introduce to your pool. You can choose to measure pH using a chemical test strip or chemical test kit but neither will give you the accuracy or ease of use of a pocket pH meter. pH uses a scale of 0 to 14 and is a measure of how acidic or alkaline the water is. pH values above 7pH mean the water is alkaline, whereas pH values below 7 mean the water is acidic. Therefore a pH reading of 8pH would indicate an alkaline and a pH reading of 6pH would indicate an acidic reading. It is worth noting that pH increases ten times in strength for every unit of pH, therefore 5pH is 10x more acidic than 6pH! The ideal range for a pool or hot tub is between 7.2pH and 7.6pH A pH tester will provide direct readout of pH on a digital scale with a high degree of accuracy and resolution. Compared to a test kit which might give a scale from 6.0 to 8.0pH, a digital tester reads all the way from 0 to 14pH and with 0.1 or 0.01pH resolution (depending on model). pH testers don’t require the addition of any chemical or reagent. To use, you simply switch ON, then dip the tester into the water and get a pH reading directly on the digital display. As you can probably tell, we really rate them for pool and hot tub use! ✔Top tip: Always measure your pH when the water is at the right temperature! This is because at different temperatures the pH of the water will change, so if you measure the pH when the water is cold and then heat it up you’ll find the pH value has altered.

What are the Key Aquarium Parameters?

A healthy aquarium begins with maintaining adequate water quality to ensure a healthy aquatic environment. Below you will find the parameters you should be monitoring and the typical values of both freshwater and saltwater aquariums. Regular monitoring and adjustment of the water quality is crucial for the health of your aquarium and it is important to test the water regularly.  Setting a schedule and being consistent in water testing will greatly improve the appearance and health of the fish in your aquarium. Freshwater Aquarium Parameters The following table represents a general guide to the most popular types of freshwater aquariums and the water parameters that require monitoring. Keep in mind that certain species or stages of the life cycle may have more specific requirements. Freshwater Aquarium Parameters Guide Parameter  Freshwater tropical African cichlids Discs Planted tanks Shrimp tanks pH 6.5 - 7.5 7.8 - 8.5 5.0 - 6.8 6.0 - 7.5 6.5 - 7.5 Temperature 22 - 28˚C 22 -  28 ˚C 27 - 30˚C 22 - 27˚C 22 - 28˚C Ammonia 0 ppm 0 ppm 0 ppm  0 ppm  0 ppm   Nitrite 0 - 10 ppb 0 - 10 ppm 0 - 10 ppb  0 - 10 ppb  0 - 10 ppb   Nitrate <50 ppm <50 ppm <30 ppm <30 ppm  <30 ppm   Alkalinity 65-135 ppm 165 - 300 ppm 50 - 100 ppm 50-135 ppm  50-135 ppm   General hardness 65-200 ppm 200 - 335 ppm 50 - 100 ppm 50-135 ppm 50-135 ppm   Saltwater Aquarium Parameters The following table represents general guidelines for water parameters for reef aquariums, fish-only saltwater aquariums, and coral reefs where many marine ornamentals occur naturally. Natural marine environments are used as a guide for home aquariums to mimic a similar environment. Fish-only saltwater aquariums generally have a wider fauna accepting water parameters, while more sensitive coral reef aquariums require stricter limits. Some marine species may have more specific requirements and it is important to research each inhabitant before introducing it to the aquarium.  Saltwater Aquarium Parameters Guide Parameter Reef aquarium Fish only Nature (coral reef) * Temperature 24 - 28 ° C 22 - 26 ° C 28 ° C Salinity 1,023 - 1,026 (32 - 35 ppt) 1,020 - 1,025 1,025 - 1,027 (34 - 36 ppt) pH 8.1 - 8.4 8.1 - 8.4 8.0 - 8.5 Ammonia (NH3) 0 ppm 0 ppm Close to zero Nitrite (NO2)  0 - 150 ppb 0 - 150 ppb Variable (typically <0.1 ppb) Nitrate (NO3) Low values are preferred <30 ppm Variable (typically <0.1 ppm) Phosphate (PO4) <0.05 ppm <0.2 ppm 0.005 ppm Match <20 ppb <100 ppb 2 ppb Alkalinity 8 - 12 dKH (142 - 215 ppm) 8 - 12 dKH (142 - 215 ppm) 7 dKH (125 ppm) Calcium 380 - 450 ppm 350 - 450 ppm 380 - 420 ppm Magnesium 1,250 - 1,350 ppm 1,150 - 1,350 ppm 1,280 ppm Iodine 0.06 - 0.10 ppm 0.04 - 0.10 ppm 0.06 ppm Potassium 380 - 420 ppm 380 - 420 ppm 400 ppm Strontium 8 - 14 ppm 4 - 10 ppm 8 - 10 ppm Silica 0.06 - 2 ppm <3 ppm <0.06 - 2.7 ppm ORP 250 - 400 mV 250 - 400 mV Variable Iron 0.15 ppm ~ 0.15 ppm 0.00006 ppm Boron <10 ppm <10 ppm 4.4 ppm * Please note that natural coral reef values are based on typical surface ocean values and may change. ppm = parts per million ppb = parts per billion ppt = Parts per thousand dKH = degrees of carbonate hardness

Introducing the HALO 2

The pH electrodes are designed for intended test samples. Benefits include:   Calibration data tagged to all readings to ensure testing procedure compliance User assisted experience through calibration reminders, pH probe condition and measurement alarms Waterproof to IP65 standards Automatic Calibration Automatic Temperature Compensation Large LCD One Button Operation   Choose your parameter: Lab, Field, Cosmetic Creams, Soil, Wine, Beer, Meat, Chocolate, Bread and Dough, Cheese, Milk, Sushi, Skin, Leather and Paper. About the Hanna Lab App When used with HALO 2, the Hanna Lab App turns a compatible smart device into a full-featured pH meter. Functions include calibration, measurement, graphing, datalogging, and data sharing as well as Good Laboratory Practice (GLP) capabilities. Measurement and logging start at one second intervals as soon as HALO 2 is connected.

How to Look After pH electrodes - 10 Top Tips

Best testers and practice for Aquarium water testing?

Here at Hanna, we pride ourselves on offering aquarists accurate and trustworthy equipment to monitor aquariums on a daily basis.  Below, you will find a guide to the type of equipment and parameters you will need to test for. Plus, check out our webinar for Aquarium Water Testing Best Practice.

How important is pH in growing?

Whether you are a home gardener or manage commercial greenhouses, testing, monitoring and keeping tabs on growth parameters all help to maximise efficiency, quality and quantity. The GroLine range provides the means to continuous monitoring and testing parameters such as pH, conductivity (EC & TDS), and temperature, including hydroponic nutrient solutions. Simple to use, Hanna makes the testing and monitoring equipment with hydroponics, aquaponics, and greenhouse growers in mind. It is not just the nutrient feeds that need testing. Soil, fertiliser, water, and even the effluent waters will all need monitoring, as well as the finished product itself. Hanna’s range includes monitors, spot testers, and more complex meters for start to finish growing. pH is so important in helping plants to flourish. We have a guide here on the ideal pH level for your chosen crop.   Optimum pH levels for plants Vegetable plants Optimum pH Artichoke 6.5-7.5 Asparagus 6-8 Barley 6-7 Beans 6-7.5 Brussels Sprout 6-7.5 Corn (Maize) 6-7.5 Cucumber 5.5-7.5 Early carrot 5.5-7 Early potato 4.5-6 Egg plant 5.5-7 Late carrot 5.5-7 Late potato 4.5-6 Lettuce 6-7 Melon 5.5-6.5 Oat 6-7 Onion 6-7 Pea 6-7.5 Pepper 6-7 Pumpkin 5.5-7.5 Rice 5-6.5 Soybean 5.5-6.5 Spinach 6-7.5 Strawberry 5-7.5 String Beans 6-7.5 Sugar beet 6-7 Sunflower 6-7.5 Sweet potato 5.5-6.5 Tomato 5.5-6.5 Watermelon 5.5-6.5 Wheat 6-7 Garden and Flower Plants Optimal pH Acacia 6-8 Acanthus 6-7 Amaranth 6-6.5 Bougainvillea 5.5-7.5 Dahlia 6-7.5 Erica 4.5-6 Euphorbia 6-7 Fuchsia 5.5-7.5 Gentian 5-7.5 Gladiolus 6-7 Hellebore 6-7.5 Hyacinth 6.5-7.5 Iris 5-6.5 Juniper 5-6.5 Ligustrum 5-7.5 Magnolia 5-6 Narcissus 6-8.5 Oleander 6-7.5 Paulownia 6-8 Primula 6-7.5 Rhododendron 4.5-6 Roses 5.5-7 Sedum 6-7.5 Sunflower 6-7 Tulip 6-7 Viola 5.5-6.5 Orchard Plants Optimal pH Apple 5-6.5 Apricot 6-7 Cherry 6-7.5 Grapefruit 6-7.5 Grapevine 6-7 Lemon 6-7 Nectarine 6-7.5 Orange 5-7 Peach 6-7.5 Pear 6-7.5 Plum 6-7.5 Pomegranate 5.5-6.5 Walnut 6-8

Does your electrode need cleaning?

General cleaning practises below can be used for any Groline pH electrode.

Pool and Hot Tub testing explained

The What, Why and How of Pool and Hot Tub testing Whether you are a new pool or hot tub owner or an experienced pro, we hope you will find information here to help you maintain pool & hot tub water in optimal condition. We’ve put together this short guide which should provide you with the What, Why and How of testing pool and hot tub water.   The What? First off, what do you need to test for? Well, the main parameters for pool and hot tub water are shown below, but don’t worry if it looks a long list, you won’t have to test all of these, all of the time! pH Chlorine Cyanuric acid Conductivity in µS/cm and TDS in ppm Total alkalinity  Total hardness (Calcium hardness) Cyanuric acid Nitrate & Phosphate  Turbidity   The Why? Correct chemical control of your pool or hot tub water is essential to ensure bather safety and to maximise life of the mechanical and electrical parts of your system. Here we try and explain why each of the parameters you measure in your pool is important and provide guidance on what the optimal levels should be. pH Ideal range between 7.2pH and 7.6pH pH uses a scale of 0 to 14 and is a measure of how acidic or alkaline the water is. pH values above 7pH mean the water is alkaline, whereas pH values below 7pH mean the water is acidic. Therefore a pH reading of 8pH would indicate an alkaline and a pH reading of 6pH would indicate an acidic reading. It is worth noting that pH increases ten times in strength for every unit of pH, therefore 5pH is 10 times more acidic than 6pH! pH is the first measurement you should make because pH influences all the other parameters, so it’s very important to have the correct pH value and measuring it correctly before doing anything else! ✔Top tip: Always measure your pH when the water is at the right temperature! This is because at different temperatures the pH of the water will change, so if you measure the pH when the water is cold and then heat it up you’ll find the pH value has altered. Chlorine This is the most commonly used sanitiser in pools and hot tubs. Provided the pH of your water is in the correct range, then it is an extremely effective chemical. In order to ascertain the level of chlorine in the water which is available to act as a disinfectant we measure free chlorine, in effect this is the measure of the active ‘part’ of the chlorine in the water. We also measure something called combined chlorine, which is the measure of the chlorine that has done its job and disinfected the water. Depending on region and local authority requirements, for pools and hot-tubs the accepted range for combined chlorine is generally between 0 to 0.6mg/L. The ideal range is a little harder to recommend as it depends a little on bather load, frequency of pool use, pool or hot tub location, but as a general guide: Free chlorine ideal range for indoor pools 1 to 1.5mg/L Free chlorine ideal range for outdoor pools 1.5mg/L to 3mg/L Free chlorine ideal range for hot tubs 3 to 5mg/L ✔Top tip: You’ll also hear the term ‘total chlorine’ and might be wondering what it is. Well, it is simply the total. Total chlorine = free chlorine + combined chlorine.   Cyanuric Acid Ideal range 20mg/L to 70mg/L (depends on local standards and if pool is outside) Cyanuric acid is added to pools to protect the chlorine from degradation by ultra-violet light, which is present in sunlight. Therefore, it is a useful additive for outdoor pools and hot tubs. However, it does have a couple of drawbacks which are worth noting. If you’ve ever heard the expression “too much of a good thing”, then please bear that in mind with cyanuric acid. If more than 70 mg/l of cyanuric acid is present, the free chlorine will become too stable and the active part of the free chlorine will substantially decrease. What is even more frustrating is that the usual method employed to measure free chlorine in a pool (known as the DPD method) doesn’t ‘see’ the difference of free chlorine with cyanuric acid or without! What happens when your cyanuric acid level is too high? Sadly, the only reliable method to remove cyanuric acid from swimming pools is through draining and/or dilution. As cyanuric acid doesn’t get ‘used up’, this is a frequent issue we come across. There is nothing as frustrating or time consuming, (not to mention the cost), of draining a pool of water just because the cyanuric acid levels had got too high for the chlorine to do its job. ✔ Top tip: Stabilised chlorine contains cyanuric acid. Whether you buy stabilised chlorine as tablets or in powder/granule form, it’s worth remembering that the term stabilised means it has cyanuric acid present. ✔ If you’ve ever had a pool and watched it gradually go green with algae, even though your meter tells you there is plenty of chlorine present, then it’s most likely a result of too high a level of cyanuric acid even if you think you haven’t been adding any!   Conductivity Is a measure of the ability of a material in the water to conduct an electric current and is conventionally expressed in µS/cm (microsiemens/cm) or mS/cm (millisiemens). For anyone with a salt controlled pool (using a salt electrolyse system) then it is a useful measurement to determine when to back-wash the pool. Back-wash if the conductivity reading is greater than 2100 µS/cm. ✔Top tip: Accurate conductivity readings are very dependent on temperature, so it is important to allow your conductivity meter time to reach the temperature of the water you are measuring otherwise an incorrect result will be obtained. Luckily most conductivity meters have a thermometer built-in, so it’s just a case of waiting until the temperature readout is stable before taking the conductivity reading.   Total Dissolved Solids TDS or Total Dissolved Solids is a measure of the total ions in solution and in terms of a pool or hot tub, it is a measure of the concentration of the dissolved compounds in the water which could be from the chemicals you’ve added, but also from what the bathers introduce to the water. Ideal range: TDS should be no more than 1000 mg/l higher than the incoming fill water   Total Alkalinity Correct levels of alkalinity prevent large swings in pH thus making it much easier to control the pH of your pool or hot-tub water. It is primarily a measurement of the bicarbonates in the water and is expressed in mg/L CaC03 (calcium carbonate). Ideal range: 75 to 120mg/L CaCO3 ✔Top tip: If you find it’s difficult to control the pH of your pool water and every time you add pH plus or pH minus the pH values seem to run away with you, then it’s worth checking your total alkalinity and ensuring you’ve got the right amount in your pool to buffer and protect against large pH swings.   Total Hardness Total hardness is the sum total of the calcium and magnesium hardness of the water, although the vast majority will be calcium and therefore, a reading expressed as mg/l CaCO3. It is a useful measurement as too much calcium hardness in your water will cause scaling of heaters, pumps, jets and pipework. If hardness is too low, corrosion is possible because of the lack of a thin layer of calcium to protect against pitting corrosion of metal parts allowing the acid in the pool to attack the components. Ideal range: 80 to 200 mg/l CaCO3 ✔Top tip: If your water appears cloudy, it may well be an indication of too high a value of calcium hardness.   Nitrate and Phosphate Both these compounds can cause eutrophication and a clear sign of them present in the water is if the pool water suddenly goes green due to rapid algae growth as they are both nutrients. Both are naturally present in water although, generally, in such low levels as to not present a problem. Ideal range for Nitrate is less than 50 mg/l NO3 Ideal range for Phosphate is less than 2.5 mg/l PO4 ✔Top tip: If you find you’re using a lot of chlorine and your pool water is still green, then you’re nitrate or phosphate levels are probably higher than they ought to be! Turbidity Turbidity is a measure of how cloudy water is and an indicator of pool water chemistry or filter issues. From a safety perspective, it is an important measurement in pools as water with a high turbidity value might make it difficult to see someone in trouble at the bottom of a pool. Ideal range should be less than 0.5NTU   The How?   There are a wide variety of methods to measure pool and hot tub chemicals, ranging from test strips, liquid chemical test kits, electronic photometers which utilise tablet/liquid or powder reagents and direct reading digital meters. The accuracy and ease of use of the various methods are reviewed below, but first we need to cover taking a water sample. Taking a water sample In order to maximise the accuracy of your reading it is important to try to obtain a representative sample of the water in your pool or hot tub. Where you sample from is important: ✔ Always use a plastic container and NOT glass. Broken glass in a pool or hot tub is near invisible and thus a real safety issue. ✔ Always use a clean plastic bottle or sampling container, we find used plastic drinking water bottles idea. ✔ Hold it upside down so the opening is facing the floor of the pool or hot-tub ✔ Insert the bottle into the water at least to the depth of your elbow and only then turn it the right side up to collect the water sample from below the immediate surface water. ✔ Avoid taking a water sample near the return jets or skimmer openings if at all possible   Options for testing pool and hot tub water Test Strips A common way of measuring the parameters in your pool or hot tub is to use a chemical test strip - a small section of plastic impregnated with a series of chemicals which individually react with certain parameters in your water. Thus, a chemical test strip is quick and easy to use, but in terms of accuracy, there are some significant issues when using them. They require the user to wait a certain number of seconds for the chemical reaction to take place, and then they require the user to match the developed colour with a colour chart supplied. As we all see colour slightly differently, and because most of us don’t wait the required time for the colour to fully develop on the test strip, they may be a good indication of what is going on in the pool water, but not a particularly accurate way of getting an absolute reading. Pros ✔ Low cost ✔ Easy to use ✔ Fast results ✔ Can test more than one parameter at a time Cons × Not that accurate in use × Need to allow correct time for chemical reaction and colour to develop × Need to dip stick for correct amount of time in the water × Relies on the human eye to deduce which colour it most closely matched on the chart × Must be stored in a sealed container out of sunlight, results WILL vary and the test strips degrade if left out in a humid area (like a pool plant room for example!) or in direct sunlight, such as beside an outdoor pool in the summer!   Liquid Chemical Test Kits These usually comprise a plastic cube which is colour graduated or a wheel with different shades of colour around the perimeter. The idea behind them is the same as the chemical test strips in that a colour develops in the water you are sampling after you have added the supplied chemical (called reagent). You then compare the developed colour with that of the printed colour on the plastic cube or wheel. Like chemical test strips, these are only as accurate as the person using them and are susceptible to the same issues such as the importance of allowing the correct time to elapse before taking a reading and the issue of colour interpretation. Pros ✔ Relatively low cost ✔ Easy to use ✔ Fast results ✔ If used correctly, the potential to give better accuracy than a chemical test strip   Cons × Not as easy to use a chemical test strip × Need to allow correct time for chemical reaction and colour to develop × Still relies on the human eye to deduce which colour it most closely matches × Liquid reagents must be store out of sunlight and tablets should be stored in an ambient environment and not in a hot and humid plant room.   Electronic Photometers and Colorimeters A photometer and a colorimeter are one and the same thing, it is just some manufactures like to call them photometers and others refer to them as colorimeters. To save saying both names we will just use the word ‘photometers’ in this text. Photometers work in the same way as a chemical test strip or chemical test kit; by electronically examining the shade of colour developed in a water sample and giving a result. They are able to operate at a specific wavelength rather than the full visible light spectrum and don’t rely on human eye ‘interpretation’ of colour. As a result they are significantly more accurate than either test strips or chemical test kits and give a direct readout of chemical parameter in mg/L. Pros ✔ High levels of accuracy (as good as +/-0.01mg/L) ✔ Direct readout in mg/L of the parameter you are measuring ✔ Pre-programed with the correct ‘waiting time’ for the colour to develop ✔ No need to rely on colour interpretation by human eye ✔ Available as single parameter or multi-parameter instruments Cons × More expensive as one has to purchase the photometer × Liquid reagents must be stored out of sunlight and tablets should be stored in an ambient environment and not in a hot and humid plant room   Direct read digital meters Although it is not possible to measure all the parameters in a pool without some form of chemical reagent being added to the water, there are some parameters which can be measured by direct read digital meters. Of all of these, pH is really the one we’d recommend getting a direct read digital meter for. Phenol red tablets and liquid test kits are not that good at getting accurate pH results, and colour interpretation on a chemical test strip can be at best half a pH unit out from the true value due to the reasons already mentioned. A digital pH pocket test instrument provides direct readout of the pH of the pool with up to +/-0.01 accuracy. They are easy to use and quick to provide results. Simply switch on, place the sensor in the water and get a direct readout of the pH. Other direct read digital meters which are also available for the pool and hot tub market are pocket testers for Conductivity, TDS (Total Dissolved Solids), ORP (Oxidisation Reduction Potential) and, of course, temperature. Pros ✔ No need to add chemical reagents ✔ Easy to use ✔ Direct readout of the parameter you want on the digital display ✔ High degree of accuracy   Cons × Although not expensive, they do cost more than chemical test strips × Some models require calibration and a degree of care or maintenance to ensure accuracy

Testing for salt in food using titration

Why do I need to measure salt in food? Salt plays a vital role in transporting water around the body, and in transmitting messages between the brain and the rest of the body. However, as with most things, too much salt in our diets can lead to problems such as water retention, raised blood pressure, and a higher risk of heart attack, kidney disease and stroke, so it’s worth keeping within safe limits. Many everyday foods are not obviously salty, but they can contain high amounts of 'hidden salt' and with growing health concerns surrounding salt posing significant health risks, people are increasingly becoming more health conscious. Many manufacturers have recently made some positive changes to the amount of salt they add and government guidelines have made it mandatory to display salt content in all consumable products. Current national health guidelines state the reference intake of salt for an adult should eat no more than 6g of salt a day (2.4g sodium) – that's around 1 teaspoon. Introduction of a traffic light system on products has also been introduced to warn consumers High: more than 1.5g of salt per 100g (or 0.6g sodium, medium: 0.3g-1.5g Low: 0.3g of salt or less per 100g (or 0.1g sodium). Testing salt content can allow you to be certain of the salt content of your product, ensure that you are adhering to government guidelines and presenting a safe measure of intake for the consumer.   How can I measure salt content? Salt content can be measured via titration. In this procedure, NaCl concentration is determined by the combination of reagent and ion selective electrode that detects ionic activity which is directly measured to establish the concentration of the salt compound NaCl.   The Hanna Automatic Potentiometric Titration Systems The use of the Hanna Automated titration system provides a quick and simple way to measure your acidity. This test can be simply programmed into the customisable system and saved for future use. Press ‘start’ and the Hanna titration system will automatically perform the reaction and calculate your result fast, accurately and reliably.   Which model is best suited for my needs? *Please speak with a member of our sales team for further advice and assistance.*   SOP - Salt in Food Theory This application note details a simple procedure for determining the salt (NaCl) present in food/beverage using the Hanna automated titrator and a Hanna silver/sulphide ISE electrode. The reaction below is performed through titration of a wine sample. The sample is titrated with silver nitrate in the presence of a silver ion selective electrode. The silver ions that are free in solution upon titration are determined and the calculation of NaCl present that must of formed with the Ag ions are calculated and directly proportional to the salt present in the sample as NaCl. NaCl (aq) + AgNO^3 (aq) is the following: NaCl (aq) + AgNO3 (aq) → AgCl (s) + NaNO3 (aq).   Equipment: HI-4115 silver ISE electrode & HI-7072 Potassium Nitrate electrode filling solution Beaker   Reagents: HI-70422 0.1M silver Nitrate HI-70427 1.5M Nitric Acid HI-4015-01 0.1M Silver standard Solution De-ionised water   Procedure Weigh 5g of sample and accurately record weight. Add 100ml of de-ionised water to the sample and homogenise. Filter the blended solution through a muslin cloth into a beaker to remove particles. Add 2ml of 1.5M HNO3 Nitric Acid using a pipette to the sample solution. Ensure the burette is full and containing titrant 0.1 Silver Nitrate Place beaker into position, submerging the electrode and temperature sensor into the sample solution with the titrant dispensing tip just over the solution. Press ‘Start’ *When the titration has finished the titrator will display your results on screen.* *Homogenisation may be done using a hand blender.*

Comply with food temperature regulations

HANNA manufactures products with the necessary accuracy and reliability to check the quality of food in all phases of preparation and distribution while maintaining compliance with the law. At Hanna, we recognise that temperature is an important parameter throughout many stages of the food production process; from manufacturing, pasteurisation, to storage - temperature measurement is essential. Indeed, our food thermometers are relied on by the main UK supermarkets and high street restaurant chains. There are a variety of thermometer technologies that we sell to help you with your process, and meet legal requirement, by checking those important temperature measurements. Here is a brief introduction to our range, and some help in what they may be used for. Thermocouple thermometers provide a fast response and are capable of measurement at very high temperatures, they also provide moderate accuracy. Thermistor thermometers offer high accuracy with a moderate response time within a limited temperature range. Hanna offers a variety of thermometers and application specific probes for all temperature measuring needs. If you are looking for something simple, then look no further than at the HI-151 Checktemp 4. It is the perfect portable, high-accuracy thermometer for home and professional kitchens. The sharp, stainless steel, fold-out probe is ideal when testing fresh, cooked and semi-frozen food. Six colour-coded thermometers are available to meet the food hygiene and Hazard Analysis Critical Control Point (HACCP) regulations.   Why measuring temperature in food industry sectors is important and the temperatures to aim for Meat The temperature of meat at slaughterhouses is a vital quality control test and needs to be checked at various points of production. Fresh meat should be stored at about 2°C. For deep-freeze meat in storage, it should have an internal temperature around -22°C with the surface temperature reaching -35°C. In order to thaw the meat properly, the surrounding temperature should be 7°C.   Ham and Sausages The temperature of salted meat stored for several months is around 2°C. Afterwards, the product is rinsed and dried at around 25°C prior to maturing at a preset temperature for a particular product. For sausages, the mixed ingredients are cooked at a certain temperature and then cooled at around 5 to 15°C. Milk and Dairy Products Milk is checked for impurities and bacteria upon collection. During storage, the temperature of milk is normally kept below 5°C. In order to slow down cream formation, milk is homogenized at about 60°C. The pasteurisation of milk results in the reduction of microorganisms by 95% and is attained by raising the temperature to over 72°C. For UHT (ultra heat treated), milk is heated to 135/150°C in a pressurised vessel for a few seconds. If the process is repeated for several minutes, all microorganisms, including spores, are destroyed and the sterilised milk will have a 12 month shelf life. For cheese, temperature needs to be adjusted before and during various processes, for example, when rennet is added. Temperature in the maturation chamber also determines the period of maturation needed. Likewise, temperature is important in the production of butter. For example, skimmed milk is separated from cream at around 55°C and the cream is then cooled to about 8°C. The temperature of incoming milk is raised to 45°C before the addition of a culture for yogurt manufacturing. In order to denature the whey proteins, milk is raised to very high temperatures. The incubation temperature is maintained for a few hours prior to its cooling to about 10°C.   Chocolate Fermentation of cocoa beans is started by increasing the temperature to about 50°C. At different stages of chocolate manufacturing such as crystallization, accurate temperature measurement is a must. Once the chocolate is ready, the storage temperature should be monitored to ensure that it stays in the 15°C range.   Confectioneries In confectioneries, temperature of the sugar syrup will dictate the consistency of the final product. For caramel or other soft candies, the sugar syrup is heated to 121°C; a brittle hard candy, such as a lollipop, requires the sugar syrup to be heated to 148°C. A few degrees temperature variation may cause significant differences from one batch to the next. Thermistor thermometers, such as the HI93501, offer a high level of accuracy for accurate temperature monitoring in the confectionery production process. Bread and Pasta The temperature of stored grain in silos is controlled to ensure that premature fermentation does not occur. During pasta production, water at about 25°C is added to wheat flour during fermentation of dough for bread-making, the temperature is kept at around 30°C. The oven temperature for baking should be around 260°C and once baked, bread is cooled to room temperature. For semi-finished products that can be flash-baked, the dough has to be stored at very low temperatures. Beverages The temperature of spring or deep well waters that are extracted for beverage production must be continuously monitored to ensure purity. During the production of soft drinks, syrup is pasteurized before being added, to prevent bacteriological problems. In order to prepare fruit juices, fruit pulp is heated to just below boiling point for a few seconds to reduce the presence of microorganisms. During both of these processes, accurate temperature monitoring is crucial.   Coffee Coffee is one the favourite beverages consumed by billions of people worldwide. Coffee, no matter the brand and quality, can be affected drastically during the brewing stage. The water quality plays a vital role in determining the taste of the beverage. An equally important physical factor is the temperature of the water. Brewing is a chemical reaction between hot water and coffee. Overall, the brewing process extracts compounds from the coffee grounds; how these compounds are extracted is temperature-dependent. Slight variations in temperature affect the taste and aroma of the coffee. Colder water will result in less extraction, leaving the coffee tasting sour, weak and diluted, whereas, water that is too hot will cause over extraction, resulting in bitter and burnt tasting coffee. In order to invoke an aroma, coffee beans are heated up to 200°C. During roasting, the temperature is closely monitored. In order to provide a long shelf life, the finished product is frozen at -40°C prior to drying. To produce a good coffee, it is important to ensure that the temperature of coffee machines does not exceed 80°C.   Brewing At its core, all beer is made from the same 4 ingredients: water, yeast, hops and grain. Some brewers will choose to modify this basic recipe to include spices or fruits. Regardless of additives, all beers can be classified as either an ale or a lager based on which yeast is used: ale yeast or lager yeast. Temperature plays an important role in yeast fermentation and can be a deciding factor as to which style is chosen. To begin, milled grains, such as barley and oats, are added to a large vessel called the mash tun. Hot water is added, activating malt enzymes from the grains which then convert the starches into fermentable sugars. The next step, called lautering, separates the sugary liquid known as wort from the spent grains. In order to end enzymatic activity, the temperature is brought to over 77°C, a process known as mashing out. The wort and some water is sent through the mash, removing any final sugars. Brewers can use temperature and time to manipulate which enzymes are active to bring out the desired sugars and influence taste. In general, lower mash temps increase fermentability while higher temperatures decrease it. The wort goes through a series of boils while hops and other additives are added, and once cooled down, the yeast is pitched and thus begins the process of fermentation. Over the course of the next 7 to 10 days, the yeast will convert the simple sugars in the hopped wort into alcohol and carbon dioxide. During fermentation, sugar from the grains are converted to ethanol and carbon dioxide via yeast. Ale yeast ferments best at higher temperatures, typically 18-21°C. At these warmer temperatures, fermentation speeds up, taking less time and also producing esters and phenols that add to the flavour. Lager yeasts ferment best at lower temperatures around 10-13°C. These yeasts tend to ferment slower, producing fewer phenols and creating a flavour more influenced by the hops and grains. Sanitisation of Machinery The temperature of cleansing agents, together with their concentration, have a significant bearing on how effectively the machinery is sanitised. The temperature for fermentation vessels can range from room temperature to 40°C. For milk and yogurt, tanks may reach 70°C and as high as 150°C for steam sterilisers. In addition, regulatory bodies recommend a certain minimum temperature for cleaning agents to be effective; this can vary from 24°C for iodine and ammonia and 49°C (120.2°F) for chlorine. Refrigeration for transportation Hanna also sells a range of thermologgers designed for keeping records of temperatures of goods being transported.

Choosing the right electrode for your application

At Hanna, we have over 100 pH electrodes to choose from and it can be quite a challenge to get the right one if you don’t know what you are looking for. Here, we will cover how our electrodes are made and what to consider when you are making your choice. There are quite a lot of variables that need to be considered and whether to go for the wireless option now with our HALO range. These include: The specification of the glass membrane Glass membrane profile (shape) Junction type Electrode body material All about the glass membrane The membrane, the main sensing part of the probe, can be affected by high temperature and each electrode is given a maximum temperature level. Excessive temperatures for electrodes can have a significant impact on the electrode life. When choosing an electrode, take into consideration which one will suit your application best. General purpose glass (GP) Our general purposed hydrogen sensitive glass provides the greatest response over the entire pH range and can be used for a wide variety of applications. Low temperature glass (LT) This type of glass has a lower impedance and is suitable for samples at lower temperatures and lower conductivities. High temperature glass (HT) Designed for extended use at elevated temperatures where glass impedance is known to decrease, high temperature glass offer a higher resistance making it possible to obtain accurate results with excellent response times. Hydrofluoric acid glass (HF) Glass dissolves rapidly in Hydrofluoric acid, so we offer HF resistant glass for aggressive applications containing fluoride ions. HF glass membranes last ten times longer than standard GP glass formulations in these conditions. Bulbs style profiles have the greater area of contact, Spear electrodes are ideal for semi-solids, creams and sauces etc. Surface electrodes are also great at small volume samples when the sample is placed on a microplate slide for example.   Glass membrane profiles There is then the shape to consider. Again, consider what you are testing before making your choice. Spheric profile For general use in aqueous solutions, provides a wide surface area for liquid contact. Conic profile Best for slurries, emulsions, semi-solids and solids. Well suited for samples such as soil, gels, sauces, cheeses and meats. Flat profile Allows for direct surface pH measurement. Ideal for testing the pH of skin, leather or paper. Dome profile Similar to a spheric profile, the area used where a smaller profile is required in electrode construction such as in titanium bodied electrodes.   What Junction type should you choose? When new, the junction in an electrode will be white/cream colour. As use continues, the junction will grow darker, and can indicate possible contamination where the sample enters the electrode. Some glass electrodes have multiple junctions to help measure samples that are complex. Here are the main junctions to consider. Porous ceramic Most commonly used because it easily fuses with electrode glass and has a similar coefficient of expansion. Porous PTFE One of the most chemically resistant junctions available, it is ideal for industrial applications because of its chemical resistance and durability. PTFE Sleeve Ideal for samples with high amounts of solids such as slurries, sauces and wine must. The sleeve allows for high electrolyte flow and prevents clogging. Fibre wick Also known as a cloth junction, it is typically used in titanium bodied and gel filled electrodes. Ideal for field use, the junction’s renewable surface allows for a quick refresh when readings become unstable or erratic. Open Utilise a special formulation of gel electrolyte which directly contacts the sample. Offers low contact resistance coupled with a low clogging potential. These are ideal for food solids, semi-solids and emulsions.   Considering Electrode bodies Plastic bodied probes are a favourite in applications where operatives can be a little heavy handed! The point to think about here is that if there are solids in the sample they can get stuck between the castellation and the bulb. The bulb can be easily broken when teasing lumps out of the end of the probe. Glass body electrodes is resistant to a wide variety of chemicals, is easy to clean and transfers heat easily making it the stable of pH electrode body materials. They are ideal for a wide range of laboratory applications. PEI body electrodes or Polyetherimide is a high performance durable plastic that offers excellent chemical resistance against aggressive chemicals. Rugged and resilient, they are ideal for environmental and industrial applications. PVDF body electrodes or Polyvinylidene fluoride is food grade plastic that is also chemical and solvent resistant. It is durable and easy to clean and is ideal for electrodes used in the pH measurement of food products. Metal body electrodes - We manufacture electrodes in Stainless Steel and Titanium and both materials produce a rugged electrode ideal for use in a wide range of chemicals and harsh environmental conditions.   What is a combination pH electrode? Previously, it was common to measure pH using two half cells separately (reference and measuring cell). Today it is more common to use a single combined electrode which incorporates both cells as it is just so much more convenient to have a combination. A number of our electrodes also include the temperature sensor, making it much easier to use particularly in the field. So there isn’t too much to remember when making your purchase! Just: Which glass type? Which membrane? Which junction? Which electrode body material?   Plus . . .   Temperature range of sample Physical properties of the sample; flat, semi-solid, viscous, solid, emulsion etc. Pressure of the environment the electrode will be placed in Environmental conditions: lab based, field based, high humidity etc.     Using the right electrode for your application and looking after it gives you a head-start in: ✔obtaining accurate results ✔longer electrode life ✔minimising erratic readings ✔frequency of calibration   Choosing a Conductivity meter/electrode Know how to identify the conductivity probes: 1 If you see two graphite or stainless steel pins or plates then it is a two electrode probe 2 A single probe with four rings on it is a potentiometric 3 While a conductivity probe used in industrial process equipment and has a circular loop at the end and is called an inductive, electrodeless or toroidal probe       Hanna testers with two-electrode sensors come in different models for different ranges. If you are testing a variety of samples, a four-ring probe may be a better option for you. They are a good choice when you're working over a wide range and don't want to use multiple probes. If you need a probe to work with process equipment, inductive conductivity probes stand up to harsher conditions. They have higher chemical resistance and are useful in industrial applications. An important factor that you should consider when shopping for a conductivity meter is temperature. Many meters feature automatic temperature compensation to ensure that the measurement is consistent over a range of temperatures. When your sample is not at room temperature (25°C), the conductivity reading will be different: Temperature increases = ions in the solution moving faster. Meters with a temperature compensation feature make adjustments based on the temperature of your sample, providing a more accurate reading.

What are the main parameters to test in drinking and waste water?

Whilst this is not an extensive list of every parameter that is measured in drinking and wastewater, it does cover the main regular tests which are carried out to ensure drinking water is safe for human consumption and that wastewater discharged into the environment is not harmful to flora and fauna.