Published on 05/14/2020 | by Waterline Admin

As featured in waterline Spring 2020


Scale an introduction – what is scale?

In the water treatment industry scale is a term used to describe a build-up of mineral deposits on the system. The reasons for the formation of the scale can be complex. Scale can contain various chemical compounds sometimes as a mixture. These compounds are commonly formed from the dissolved inorganic impurities found in the water. A common form of scale is the deposit found in kettles in hard water areas.

Some other types of deposits are referred to as fouling which can be caused by microbiological growth or contamination from process (such as oils). If the fouling results in hard deposits it can be referred to as scale. The exact name used to describe the deposit is not important – what is important is to understand what caused the deposit so that action can be taken to remove it and avoid it reappearing.

Calcium carbonate scale (limescale) deposits can be caused by simply warming or evaporation of water containing high hardness and high alkalinity levels. However, there are several factors that can result in deposits, including:

  • • mineral impurities (also called dissolved solids) naturally found in water coming out of solution
  • • corrosion – most commonly rust deposits from the corrosion of iron
  • • incorrect water treatment (e.g. chemicals being incorrectly applied and used, insufficient bleed or blowdown)
  • • overheating, low flow or no flow
  • • contamination of the system water from any source

The appearance of a scale deposit is not a reliable way to find out what it contains. This requires chemical tests often in a specialist laboratory, although some simple site tests can give an idea of some of the components.

Why is this important?

Scale can cause problems in many types of water systems including domestic water, cooling towers, hot and cold closed water systems, steam boilers, cooling towers etc. Examples include:

  • • inefficient heating or cooling, as scale is a poor conductor of heat. This could mean a building is too hot or cold; a ruined product as it was not heated or cooled correctly; damage to equipment due to overheating or even an explosion. It also adds to running costs significantly
  • • blockages of pipe work, heat exchangers, lines to instruments and gauges etc.
  • • damage to valves and other parts of the system
  • • increase in corrosion even with the best treatment chemicals
  • • scale can provide protected conditions and surfaces on which microorganisms might grow. Some of these organisms could cause health problems (e.g. legionella) and also cause serious local corrosion

What can be done to control scale?

In order to minimise any scale in a system you need to understand the type of system, how the system operates, the source of water and its quality. The methods to control scale include:

  • • reduction in the levels of impurities in the incoming water (by pretreatment plant such as base exchange water softener, RO etc.)
  • • addition of acids – great care is needed with this method
  • • addition of chemicals known as scale inhibitors – these must be chosen with care
  • • limiting the concentration of dissolved solids by removing some system water to drain and topping up with fresh or treated water
  • • filtration to remove any deposits before they settle in the system

Usually a combination of methods will be used and expert advice should be sought.

Are there other concerns?

Whatever method of control is selected it is important that its performance is regularly checked. Some methods to control scale can cause other problems such as increased corrosion and some of the chemicals used can be toxic to people or the environment.

Diary Dates & Events

Grime Scene


Following on from the successful Grime Scene competition, we have decided to continue the theme for another year, but with a twist. This year, we are asking for photographs of the grimiest pictures you can find accompanied with another photograph of how the ‘scene’ has been improved by your maintenance or cleaning.

We will display the photographs in each of the Waterline editions throughout 2024. The ‘most improved’ picture will be chosen by WMSoc members via an online vote. The winner will receive a £25 Amazon Gift Voucher after the Winter 2024/25 edition has been published.

Please send your photographs to:

Product & Service Spotlight

Introducing B & V Chemicals' new film forming amines for closed circuits and steam boilers.

Product Launch: Film forming amines.

This all-in-one solution offers low-dose, cost-effective treatment. Improves heat transfer efficiency by removing corrosion deposits, leading to cleaner surfaces. Enhances energy and resource efficiency by reducing Total Dissolved Solids (TDS). The stable film provided by polyamines ensures superior corrosion control, promoting longer equipment lifespan.

Plus - environmentally friendly, offering a greener alternative to traditional treatments.

Contact us on ownlabel@bvwater.co.uk for further information.

How the NEW SolidTek® Biocide Feeder Package will BENEFIT YOU

SolidTek® has launched its NEW Biocide Feeder which is functional, compact, and environmentally-friendly.

Designed for use with SolidTek’s® enhanced bromine biocide, BromTek, it offers multiple benefits:

Reduced exposure to fumes and bromine dust (non-pressurised system).

Use with field proven mixed hydantoin biocide - better performance than standard bromine tablets.

Wall mounted reducing footprint of installation.

Charge with product in under 5 minutes without isolation from the system.

Product calculators and tech support available.

Lovibond MD640 Photometer (PTSA & Fluorescein capable)

Product Spotlight Drop Test Kits

How many times have you heard … ‘we’re not sure what the system volume is’. A common problem which can be expensive - wasting chemical over dosing, or underdosing so the treatment is ineffective (i.e. shock dosing a biocide). The MD640 photometer has PTSA & Fluorescein capability built in. Simply use our System Checkers to add to an unknown system and read a PTSA or Fluorescein levels to accurately identify the system volume.

The Hydrosense PRO range


The Hydrosense PRO range pioneers Legionella pneumophila detection, the cause of over 97% of Legionnaires’ disease outbreaks, by identifying all the serogroups 1-15 of this dangerous Legionella species. This easy-to-use, highly sensitive test uses unique filtration, offering a three-line test result that distinguishes between serogroup 1 and serogroups 2-15 within 25 minutes. The water test has a level of detection of 100 CFU/L and swab tests detect 200 CFU per swabbed area, providing crucial, rapid insights for water safety management.