What is hard water?
Hard water contains dissolved calcium and magnesium salts, measured in ppm as calcium carbonate. In parts cleaning it causes scale on heaters, films on parts and reduced cleaner performance; in cooling systems it is the direct source of the scale that descaling chemistry has to remove.
Hardness above roughly 200 ppm starts to show in a wash line: a white film on parts, scale on immersion heaters that reduces heat transfer, and a bath that needs more concentrate to achieve the same result because hardness is consuming part of the chemistry.
Two remedies exist. Treat the chemistry — use a cleaner with a strong chelant package so hardness is sequestered as it arrives. Or treat the water — soften or deionise the make-up supply, which is more capital but removes the problem at source.
In cooling towers the same hardness concentrates as water evaporates, which is precisely why cooling systems need both a controlled blowdown and a scale-inhibitor programme.
