The main industrial problem associated with hardness is scale and deposits formation in pipelines, boilers and heat exchange systems . Generally, industrial water relies on water softeners considering that for many applications the aim is very soft water (below 10 mg/L).
Boiler feed water is particularly sensitive to water hardness since levels higher that 8mg/L can seriously affect equipment, open the doors of unexpected repair costs and most importantly downtime.
In industrial flow-through equipment in manufacturing or cooling towers, the hardness deposits (scale) can limit the flow and slow down waterways. Other parts of equipment are vulnerable too, valves & nozzles and can interfere with the water flow and system pressure.
Problems with the pressure management can launch a chain reaction of problems, including greater pumping cost, leading to higher energy consumption and eventually causing the equipment and pipeline replacement.
Cooling towers rely on soft water to maintain the effectiveness of heat transfer, with economizing their running costs and mainly, to avoid corrosion.
Boilers rely on heat exchange between tube layer and water. The scale acts here as an insulative material, and can lead to decrease of heat exchange and overheating of the boiler tube metal, costly maintenance and repairs and shorter lifespan of the boiler.
In the following equilibrium reaction we can observe the dissolving and formation of calcium carbonate and calcium bicarbonate (on the right):
Ions causing permanent hardness of water can be removed using a water softener, or ion-exchange column.
| Classification | hardness in mg-CaCO3/L | hardness in mmol/L | hardness in dGH/°dH | hardness in ppm |
|---|---|---|---|---|
|
Soft |
0–60 |
0–0.60 |
0–3.37 |
0–60 |
|
Moderately hard |
61–120 |
0.61–1.20 |
3.38–6.74 |
61–120 |
|
Hard |
121–180 |
1.21–1.80 |
6.75–10.11 |
121–180 |
|
Very hard |
≥ 181 |
≥ 1.81 |
≥ 10.12 |
≥ 181 |
Water hardness determination is one of the main factors that must be taken into consideration during regular maintenance.
Another consideration is the role the water hardness chemistry in the water balance and any chemical or electrochemical reactions in your application.
For these reasons, the hardness of the water needs to be closely monitored and maintained at specific levels.
- changes in water appearance
- water can become more turbid /cloudy
- damage to the functionality of equipment
- clogging and blocking the flow of water in and out
Water hardness determination is one of the main factors that must be taken into consideration during regular maintenance.
Another consideration is the role the water hardness chemistry in the water balance and any chemical or electrochemical reactions in your application.
For these reasons, the hardness of the water needs to be closely monitored and maintained at specific levels.
- changes in water appearance
- water can become more turbid /cloudy
- damage to the functionality of equipment
- clogging and blocking the flow of water in and out
Hard water makes it even more tricky to achieve proper water parameter balance (pH, alkalinity, chlorine) and results in higher consumption of chemicals
How to measure
water hardness?
water hardness?
There are several methods available, from fast checking test kits, photometers to titration systems.
HANNA has developed a new “easy-to-use” solution for testing as an alternative to chemical test kits.
HI735
Hardness Low Range Checker – Checker®HC
Features at-a-glance:
- Easier to use and more accurate than chemical test kits
- Dedicated to a single parameter
- Small size, big convenience
- Ideal for: Drinking and process water, heating and cooling systems, swimming pools and spas.
The HI735 Checker®HC (Handheld Colorimeter) is a simple, accurate, and cost effective way to measure total hardness. Designed as a more accurate alternative to chemical test kits, the HI735 provides quick, accurate results in a few easy steps.
Our Total Hardness Low Range handheld checker offers you a middle ground between advanced instrumentation and your typical chemical test kit. Standard test kits have limited accuracy since they rely upon the human eye to match colors. Our handheld colorimeter eliminates the hassle of matching to a color chart by providing a direct Total Hardness Low Range result digitally.
- Range: 0 to 350 ppm (mg/L) as CaCO₃
- Get simple results with easy one-button operation.
- Don’t waste time matching to a color chart anymore, get direct results quickly.
HI97735
Total Hardness
Portable Photometer
Portable Photometer
The HI97735 Total Hardness Photometer combines accuracy and ease of use in a simple, portable design. The advanced optical system provides lab-quality accuracy while its user-friendly design is easy for any user making it the perfect photometer for your water quality testing needs. The HI97735 meter measures total hardness in water samples up to 750 mg/L (ppm) CaCO3.
- No warm up time needed before taking a measurement.
- Tutorial mode for easy step-by-step instructions.
- CAL Check for performance verification and calibration
- Easy navigation between chemical forms with a press-of- a-button:
– mg/L (ppm)
– French degrees (°f)
– German degrees (°dH)
– English degrees (°E)
Press the
key and use the functional keys to select Chemical Form.
Press Select to change the displayed chemical form to French degrees(°f)
German degrees (°dH) and English degrees (°E)
German degrees (°dH) and English degrees (°E)
Press Select to change the displayed chemical form to French degrees(°f) German degrees (°dH) and English degrees (°E)
Press the
to return to the measurement screen.
It’s available in 2 versions HI97735 & HI97735C
Each HI97735 is delivered in a cardboard box and is supplied with:
- Sample cuvette (2 pcs.)
- Sample cuvette cap (2 pcs.)
- Plastic stopper (2 pcs.)
- 1.5V AA Alkaline batteries
- Instruction manual
- Meter quality certificate
Each HI97735C is delivered in a rugged carrying case and is supplied with:
- Sample cuvette (2 pcs.)
- Sample cuvette cap (2 pcs.)
- Plastic stopper (2 pcs.)
- HI97735A – CAL CheckCuvette A
- HI97735B – CAL Check Cuvette B for Total Hardness LR, MR, HR
- Cloth for wiping cuvettes
- Scissors
- 1.5V AA Alkaline batteries
- Instruction manual
- Meter quality certificate
- CAL Check standard certificate
Reagents & ranges guidelines:
HI93735-00
(100 tests) LR – low range – 0 do 250 mg/L (ppm) CaCO₃; 0-14dH
HI93735-01
(100 tests) MR – middle range – 200 do 500 mg/L (ppm) CaCO₃; 11-28dH
HI93735-02
(100 tests) HR – high range – 400 do 750 mg/L (ppm) CaCO₃; 22-42 dH
Author:
Nives Vinceković Budor
mag.ing.chem.ing.
Nives Vinceković Budor
mag.ing.chem.ing.
With Great Product Come Great Results
