Have you heard of the term “hard water”? Well, water contains a high amount of minerals that include calcium and magnesium. It also occurs in many various water sources across the world.
Although hard water does not cause illnesses, it can lead to various problems at home appliances or factories. For instance, it can destroy heavy machinery, thus leading to expensive repairs. It even forms chalky deposits on heaters or plumbing thus keeping soaps from creating suds quickly.
To handle this issue, you will have to treat the water. But before you start looking for a water softener; let’s show you how to calculate water hardness.
What is Water Hardness?
You can define water hardness as the number of dissolved minerals in the water. Usually, hard water contains a high amount of calcium and magnesium. When you wash your body with this water, you can feel its effects on your skin.
Depending on the amount of minerals, you might feel a filmy residue on your skin, especially after washing with soap. This feeling occurs because the soap reacts with the calcium in the water to produce a “soap scum.” As a result, you will have to use extra detergent or soap with hard water.
After washing your glassware in a dishwasher, you might discover some weird spots on them. Also known as hard water residue, this film has an ugly look. However, it does not pose any risk to your health.
As mentioned earlier, homes and businesses show concern about their water hardness. After all, when it is exposed to heat, the water forms a thick residue of calcium carbonate or limescale.
Limescale can damage machinery, increase your utility bills, and affect the efficiency of your water heater. It can also block your plumbing and give your coffee maker an ugly look.
To restore the coffee maker to its original look, people sporadically toss vinegar into the pot. Since it has acidic features, the substance works by charging the limescale. Next, the charged particles move towards the water molecules, thereby making the scum easy to wash off.
Does hard water have any benefits? Yes, it has offered vital minerals that perform functions in the human body. Experts even suggest drinking water as a way to increase the mineral content in your body.
What Does Temporary and Permanent Hardness Mean?
Temporary Hardness of Water
This form of hardness results from the occurrence of dissolved calcium and sodium bicarbonates in the water. You can remove this water hardness by tossing in some lime or calcium hydroxide (lime softening).
Permanent Hardness of Water
Unlike the type mentioned above, this hardness requires special treatment due to its sulfate and chloride ions. To tackle the stubborn particles, you will need an ion exchange resin or water softener.
You can also describe permanent hardness as the sum total of calcium and magnesium hardness in water. If you want to know how to calculate water hardness, you will need a specialized test kit.
How Does A Hard Water Calculator Work?
As you already know, the hardness of water comes in two forms – permanent and temporary. With a hard water calculator, you can find overall permanent hardness. The calculator uses the formula below:
TOTAL PERMANENT HARDNESS = MAGNESIUM HARDNESS + CALCIUM HARDNESS
The calcium and magnesium stand as the concentration of both elements stated as calcium carbonate.
These values stand as the molar mass of several related compounds.
- CaC03 = 100,1 g/mol
- Ca2+ = 40, 1g/mol
- Mg2+= 24,3g/mol
The molar masses ratio can be expressed as:
- MCaCo3/MCa = 100,1/40,1=2,5
- MCaCo3/Mmg = 100,1/24,3 =4,1
This means that the overall permanent water hardness which equals CaCO3 can be determined with the formula below:
- (CaC03) = 2,5 . (Ca2+) + 4,1 (Mg2+)
So if you looking for “how to calculate water hardness formula”, you can use the one above.
Steps to Determine the Carbonate Hardness in Water (CH)
Even if the full hardness in 1 depends on the number of cations, it can also depend on the amount of anions. The latter divides the carbonate hardness/ temporary hardness and permanent hardness.
- Total Hardness TH = CH + NCH
Carbonate hardness has a relationship with alkalinity:
- CH in meq/L = [Alk in meq/L]
- CH in °dH = 809 × [Alk in meq/L]
Using water chemistry, alkalinity and carbonate hardness have similar meanings.
- Carbonate Hardness CH = Alkalinity
With the program, you can calculate total and carbonate hardness while showing output tables as below.
How Can I Measure Hardness in Water?
A measure of water hardness comes with many units. These include grains per gallon, milligrams of calcium per liter, parts per million. You might use a German degree of hardness; however, this unit fits only fish tanks.
To determine the hardness, head to a water test lab with a water sample. Then, convert the results with water hardness measures. For instance, 35ppm = 35mg of dissolved minerals per liter of water.
How to Use Soap to Determine the Grains of Hardness in A Water Sample
For this test, you will need a small bottle with a fitted cover and water level mark. In its place, you can use the marked container in a water hardness testing kit. You will also need some dish soap and a measuring cup.
Now that you know how to calculate water hardness in ppm, fill the bottle (to the mark) with water. Pour a little soap and shake to create bubbles.
If you need to add more soap to notice any suds, this shows a high amount of dissolved salts. If you use less, then the water has a low amount of minerals.
While this test shows water hardness, it cannot offer precise readings. For accurate tests, get a water test kit. You can also get these items for free or affordable prices.
How to Measure Water Hardness with a Test Kit
If you want to have a perfect idea of the water hardness in a sample, use test strips that have special pads. You can even use these products to check if your water distiller or softener works well.
Apart from these devices, some instruments can also give readings on water hardness. Now let’s see how to calculate water hardness with both items.
Measuring Water Hardness with Instruments
With the help of a colorimeter, a white light beam moves through an optical filter. Normally, the screen sends a specific color of light to the photodetector for readings.
To know the amount of colored light taken in by a sample, you will have to confirm the difference between the amount of colored light sent by a blank and colored sample.
When using a colorimetric test, you discover that the quantity of absorbed light has a relationship with its concentration. You can even notice this fact on the meter.
Measuring Water Hardness with Test Strips
If you want to know how to measure water hardness with another tool, consider getting a test strip. These simple plastic items have thick pads on their surface. With these components, the strips can detect a particular ion and create a distinct color change.
When the test strip forms a color, it’s compared to a color chart. On this printed chart, you will find color reactions at different concentrations. You can get a reading by comparing the strip to a similar color. If you can’t find one, choose the hue closest to the color on the strip.
How to Calculate Water Hardness With Test Strips
Step 1. Select Your Water Source
For untreated water hardness: To know how to measure water hardness in water coming into your location, look for an outdoor faucet. You can also check a source that has not passed through a softener or distiller.
Avoid collecting water from a garden pipe as this channel might contain particles that can affect your readings. Allow the water to flow until it reaches a stable level, as this shows that you collected water from an outside source.
For Treated Water Hardness: To check if your water softener works well, look for a water source that extends from the softener or whole house water filler.
Remove the test strip from its packaging. Ensure that its sensing pad does not touch your skin as any contact can affect potential readings.
Step 2. Insert the Test Strip
Place the test strip into a clean glass filled with the water sample. Allow to sit for 2 seconds or as instructed by the kit’s manufacturer. To avoid inaccurate results, do not leave the test strip in water for an extended period.
Pull out the strip and shake to remove excess water. Continue waving until every water drop disappears. Overall, ensure the piece shows slight wetness.
In a horizontal position, hold up the strip for between 10 – 30 seconds. Within this time, the piece can show signs of a chemical reaction
Step 3. Read the water hardness
To know how to measure water hardness with a strip, compare the color of its test pad with the water hardness chart on its packaging. Most times, the colors displayed depend on the brand of your water testing kit.
If used properly, your treated water should have a hardness reading of 0. For untreated water, expect higher values of up to 425.
Wrap Up
Water contains dissolved minerals. But when they exist in large amounts, the water becomes hard. Such metals include magnesium and calcium.
The main types of hardness include permanent and temporary water hardness. To solve these problems, you might need:
- Water softener or lime
- You can use a bottle and soap test
- for accurate results, invest in an affordable water testing kit
We hope you enjoyed our article, please feel free to share with your friends on social media. If you have any comments or questions, please drop them in the space below.
FAQs
How do we calculate hardness of water? ›
The amount of hardness is expressed in milligrams per litre (mg/L) or grains per gallon (gpg) as calcium carbonate. Hardness is calculated from the equation Hardness = 2.497 (Ca) + 4.118 (Mg).
What is the unit for calculating hardness of water *? ›A measure of water hardness comes with many units. These include grains per gallon, milligrams of calcium per liter, parts per million.
How do you calculate hardness in ppm? ›Hardness = M5 x 100000 ppm Temporary Hardness = Total hardness – Permanent Hardness.
What is the acceptable limit value for water hardness? ›The membrane manufacturers will often specify what the maximum hardness concentration can be, but industry rule of thumb is that hardness should not exceed 120 to 170 mg/L (7 to 10 grains per gallon).
Why do we measure water hardness? ›If you've noticed signs of hard water in your home, like buildup on plumbing fixtures, soap scum on shower doors or difficulty producing a lather, you may be wondering just how hard your water is. Measuring water hardness can help you determine what kind of water softener will best meet your needs.
How do you calculate hardness of a material? ›A hardness test is typically performed by pressing a specifically dimensioned and loaded object (indenter) into the surface of the material you are testing. The hardness is determined by measuring the depth of indenter penetration or by measuring the size of the impression left by an indenter.
What is hardness measured in? ›The SI unit of hardness is N/mm². The unit Pascal is thus used for hardness as well but hardness must not be confused with pressure.
What two factors are used to determine total hardness? ›The total hardness is determined by the sum of Ca and Mg: TH = (2×1.40 + 2×0.23) meq/L = 3.26 meq/L – as presented in the diagram above. We use the same example water C1. sol and add 2 mM NaOH (with button Reac) 2.
How do you calculate total hardness from calcium hardness? ›If you are comparing your own test results of calcium hardness as CaCO3 with results in publications that use units of total hardness as CaCO3, you can estimate total hardness by multiplying the calcium hardness by 1.5.
Why hardness of water is calculated in terms of CaCO3? ›When hardness is expressed as 'mg/l as CaCO3', it's calculated as if all the calcium and magnesium were present only as calcium carbonate. Hard water is a mixture of calcium and magnesium, together with bicarbonate, sulphate, chloride, etc. This makes CaCO3 calcium carbonate.
How do you convert TDS to hardness? ›
However, for estimation purposes, the water hardness can be roughly calculated by dividing the ppm (parts per million) measurement of the TDS by 10 giving a hardness value with an error of only 2-3 French degrees. TDS measurements can also be derived from relative conductivity measurement.
How is total hardness of water calculated using EDTA method? ›- Dilute 25 mL of sample (V) to about 50 mL with distilled water in an Erlenmeyer flask.
- Add 1 mL of buffer solution.
- Add two drops of indicator solution. ...
- Add the standard EDTA titrant slowly with continuous stirring until the last reddish tinge disappears from the solution.
Total hardness is a measurement of the mineral content in a water sample that is irreversible by boiling. More specifically, total hardness is determined by the concentration of multivalent cations in water. These cations have a positive charge that is higher than 1+.
What is good water quality? ›Thus, good water quality implies that harmful substances (pollutants) are absent from the water, and needed substances (oxygen, nutrients) are present. Water quality can often be defined in terms of the chemical, physical, and biological content of water.
How do I read my water test results? ›Understanding Your Well Water Test Results - YouTube
What is ppm water hardness? ›Parts per million, which can also be expressed as milligrams per liter (mg/L), is exactly what it sounds like: if you have 1 ppm water hardness, one out of one million units of your water is a hardness mineral. Depending on your water hardness test, you may have to convert between the two measurements.
What is the pH level of hard water? ›Water that is considered hard or alkaline has a pH level 8 or greater. With a pH at a level 8 or greater, might mean the water could contain ions that can form scale deposits in pipes, clothes and on dishes. The water may taste bitter and will not quench your thirst.
What is ppm water? ›This is an abbreviation for "parts per million" and it also can be expressed as milligrams per liter (mg/L). This measurement is the mass of a chemical or contaminate per unit volume of water.
What are the 3 tests used to test hardness? ›The three most commonly used are the Brinell test, the Vicker's Diamond test, and the Rockwell test. All three methods involve indentation of the material. The hardness is calculated by measuring the force applied and comparing this to some geometrical aspect of the indentation such as the surface area or depth.
How is HRC hardness measured? ›The hardness measurement is carried out using the Rockwell hardness tester. The test specimens are placed on a steel anvil and are brought into contact with a minor load (10 kg), which for testing plastic materials is a steel ball.
What are the 4 commonly used hardness testing techniques? ›
Common hardness testing types include Rockwell (indentation depth or un-recovered indentation), Knoop/Vickers, and Brinell (area of indentation). Rockwell testing is the most commonly used method by virtue of the quick results generated and is typically used on metals and alloys.
Which hardness test is best? ›The Rockwell method is the most universal because it uses both a penetrating diamond cone and a penetrating steel ball to measure the hardness of a material. The diamond cone can only be used on hardened steel and hard metals. It is not recommended below 785 N/mm² hardness. The steel ball is used with softer materials.
Which hardness test is more accurate? ›The Rockwell test is generally easier to perform, and more accurate than other types of hardness testing methods.
What is the most common hardness test? ›Rockwell
The Rockwell test is probably the most commonly used hardness test today, mainly since it is the fastest and most accurate form of testing. It is defined by the standard ASTM E18.
The two main cations that cause water hardness are calcium (Ca2+) and magnesium (Mg2+). Calcium is dissolved in water as it passes over and through limestone deposits. Magnesium is dissolved as water passes over and through
Introduction Calcium Hardness in water is determined using the preprogrammed method, T10 Ca Hard. To determine calcium, sodium hydroxide is added to a sample to raise the pH to 12 to 13. The sample is then titrated to the equivalence point using ethylenediaminetetraacetic acid (EDTA) titrant.
How do you calculate total hardness of water in ppm PDF? ›Total Hardness = 0.0125 × 105 ppm = 0.0125 × 100 (Mol. Wt of CaCO3) × 1000 (ml)ppm = 1250 ppm.
Is total hardness and calcium hardness the same? ›Is calcium hardness the same the total hardness? Calcium hardness is a measure of dissolved calcium in the water and total hardness is a measurement of the mineral content (calcium and magnesium) of the water.
What is water hardness PDF? ›It is a measure of the quantity of divalent ions (for this discussion, salts with two positive charges) such as calcium, magnesium and/or iron in water. There are many different divalent salts; however, calcium and magnesium are the most common sources of water hardness. Discover the world's research.
Why is EDTA used to determine the hardness of water? ›The hardness of water is estimated by simple titration of ethylene diamine tetraacetate (EDTA) solution. EDTA forms stable complexes with the metal ions present in the hard water since stability constants of calcium and magnesium complexes of EDTA are different, even the selective estimation of these ions is possible.
How do you calculate ppm of CaCO3? ›
The formula to convert an ion reported as "mg/l as the ion" to "ppm as calcium carbonate" is to multiply "mg/l as the ion" times the ratio of the "equivalent weight of the ion" by the "equivalent weight of calcium carbonate".
What is total hardness as CaCO3? ›| Concentration as CaCO3 | Indication |
|---|---|
| 0 to 60 mg/L | Soft water |
| 60 to 120 mg/L | Moderately hard water |
| 120 to 180 mg/L | Hard water |
| >180 mg/L | Very hard water |
TDS and hardness are water quality parameters. The main difference between TDS and hardness is that TDS include inorganic and organic substances that cannot be filtered through a filter paper whereas hardness is due to the presence of magnesium and calcium salts of carbonate, sulfate and chloride.
Can hardness be higher than TDS? ›Yes - when the water is very hard, a good percentage of the TDS will be made up of hardness minerals, but a lot of it won't be. So your TDS value will always be significantly higher than the hardness value. The other thing you can't do with a TDS meter is use it to figure out how well your softener is working.
What is a good TDS for water? ›What is the best TDS level for drinking water? Ans: Generally, the TDS level between 50-150 is considered as the most suitable and acceptable.
What is principle of EDTA method? ›EDTA is Ethylene diamine tetra acetic acid. It dissolves in water with great difficulty, but its disodium salt dissolve in water quickly & completely It is hexa dentate ligend. It binds the metal ions in water to give stable chelate complex. Hence it is called as complexometric titration method.
What happens when EDTA is added to hard water? ›As the EDTA titrant is added to a hard water sample, free Mg2+ and Ca2+ ions are captured first. After complex- ation of all the free ions, EDTA reacts with the small amount of bound metal ion–indicator complex. The metal ions are effectively removed from the indicator as EDTA binds more tightly to these ions.
What is the indicator used for estimation of hardness? ›Eriochrome Black T is a complexometric indicator that is used in complexometric titrations, e.g. in the water hardness determination process.
How is total hardness of water calculated using EDTA method? ›- Dilute 25 mL of sample (V) to about 50 mL with distilled water in an Erlenmeyer flask.
- Add 1 mL of buffer solution.
- Add two drops of indicator solution. ...
- Add the standard EDTA titrant slowly with continuous stirring until the last reddish tinge disappears from the solution.
The value of calcium hardness as CaCO3 can always be obtained by multiplying the Ca2+ concentration by a factor of 100/40, or 2.5. Another common measurement of water hardness is known as total hardness as CaCO3. This measurement takes into account both Ca2+ and Mg2+ ions.
How do you calculate the hardness of water in ppm CaCO3? ›
∴1L (1000ml) of given hard water = mg of CaCO3 eq. Total Hardness of water = 1000 V2/V1 mg/l = 1000 V2/V1 ppm.
What two factors are used to determine total hardness? ›The total hardness is determined by the sum of Ca and Mg: TH = (2×1.40 + 2×0.23) meq/L = 3.26 meq/L – as presented in the diagram above. We use the same example water C1. sol and add 2 mM NaOH (with button Reac) 2.
Why is EDTA used in hardness of water? ›EDTA is ethylene diammine tetraacetic acid. The hardness of water is due to presence of Mg2+ and Ca2+ ions in it. These ions form stable complexes with EDTA and can be estimated by simple titration.
What is principle of EDTA method? ›EDTA is Ethylene diamine tetra acetic acid. It dissolves in water with great difficulty, but its disodium salt dissolve in water quickly & completely It is hexa dentate ligend. It binds the metal ions in water to give stable chelate complex. Hence it is called as complexometric titration method.
How is water hardness calculated from calcium? ›Water hardness can be calculated by the following steps: Multiply the calcium ion concentration by 2.497. Multiply the magnesium ion concentration by 4.118. Add the two numbers to obtain the water hardness in mg-CaCo3/L .
How do you measure calcium hardness in water? ›Introduction Calcium Hardness in water is determined using the preprogrammed method, T10 Ca Hard. To determine calcium, sodium hydroxide is added to a sample to raise the pH to 12 to 13. The sample is then titrated to the equivalence point using ethylenediaminetetraacetic acid (EDTA) titrant.
Why CaCO3 is used as a standard for calculating hardness? ›When hardness is expressed as 'mg/l as CaCO3', it's calculated as if all the calcium and magnesium were present only as calcium carbonate. Hard water is a mixture of calcium and magnesium, together with bicarbonate, sulphate, chloride, etc. ... This makes CaCO3 calcium carbonate.
What is ppm equal to? ›Parts per million and parts per billion may be converted from one to the other using this relationship: 1 part per million = 1,000 parts per billion. For water, 1 ppm = approximately 1 mg/L (also written as mg/l) of contaminant in water, and 1 ppb = 1 ug/L (also written as ug/l).
How can I make 400 ppm hard water? ›Example: to prepare 1 L of 400 ppm AOAC hard water, add 4 mL AOAC Hard Water Solution 1 and 4 mL AOAC Hard Water Solution 2 to a 1 L flask and bring to volume with sterile de- ionized water. d. Determine the pH of the hard water sample. The pH should be between 7.6 and 8.0 at room temperature.
What is total hardness as CaCO3? ›| Concentration as CaCO3 | Indication |
|---|---|
| 0 to 60 mg/L | Soft water |
| 60 to 120 mg/L | Moderately hard water |
| 120 to 180 mg/L | Hard water |
| >180 mg/L | Very hard water |
How do you calculate total hardness of water in ppm PDF? ›
Total Hardness = 0.0125 × 105 ppm = 0.0125 × 100 (Mol. Wt of CaCO3) × 1000 (ml)ppm = 1250 ppm.
How is EDTA calculated? ›- Calculate the average titre of EDTA: average titre = (8.76 + 8.80 + 8.78) ÷ 3 = 8.78 mL = 8.78 x 10-3 L.
- Calculate the moles of EDTA in the average titre: moles(EDTA) = concentration (mol L-1) x volume (L) = 0.010 x 8.78 x 10-3 = 8.78 x 10-5 mol.
The classic method of determining calcium and other suitable cations is titration with a standardized solution of ethylenediaminetetraacetic acid (EDTA). EDTA has the structure shown below. Instead of repeatedly drawing this structure or writing out the chemical formula, the EDTA molecule is represented as “H4Y”.