Water Hardness

Raw water consists of much more than just the hydrogen and oxygen atoms with which we are all so familiar.  It also contains combinations of calcium, magnesium, sodium, silica and a variety of other dissolved minerals deposited from environmental sources.

Water hardness is primarily the measurement of calcium (Ca++) and magnesium (Mg++) ions in the water.  In the U.S., hardness is usually measured in ppm (parts-per-million), the molar concentration of CaCO3 which can be given by most test kits.

Other two units also used in measuring hardness:  German Degrees of Hardness (dH) and mg/l (grain/liter).  For a rule of thumb:

Hardness  PPM  dH  Mg/l 
Very soft 0 to 60 ppm 0 to 4 dH
Soft 60 to 119 ppm 4 to 8 dH 0-19 mg/l
Medium hard 120 to 179 ppm 8 to 12 dH 20-50 mg/l
Hard 180 to 239 ppm 12 to 18 dH 51-120 mg/l
Very hard 240 to 500 ppm 18 to 30 dH 121-174 mg/l
Extremely hard over 500 ppm over 30 dH >175


National Ground Water Hardness as CaCO3

Mineral deposits are formed by ionic reactions resulting in the formation of an insoluble precipitate. As these deposits build up, water-borne impurities pose special problems for our nozzle orifices (0.0045 to 0.015 dia). Even in small quantities, they change nozzle flow rate and spray patterns. This untreated water, after fogging, evaporates and leaves the heavy mineral content behind in the form of dust that deposits on all surfaces. More serious is the situation in nozzle orifices clogged as well as scaling of piping and tubes.

Water filter cartridges only remove particulate matter & debris within the water and cannot remove hardness. While our water cartridges are polyethylene so as not to allow bacteria growth to feed on the pleated media (common with cellulose or paper filters), water treatment is usually always required with city water systems to remove hardness that can/will eventually clog nozzles and tubing.

If water is too hard for a particular use, it can be softened by commercial “water softeners”, which remove calcium ions from the water and replace them with sodium ions. Or it can be run through a Reverse Osmosis or De-ionizing unit, both of which remove almost all dissolved chemicals from the water, including calcium. Any of these processes can produce water with a hardness of zero, which may or may not be suitable for all applications in general.

But for all of above, as well as other applications, de-ionization (DI) is a very effective solution. Because impurities in water exist as ions (minerals, salts with positive or negative electrical charges) they can readily be exchanged for hydrogen and hydroxide ions. This is accomplished by passing untreated water through beds of cation and anion resins.

Unlike water softening, which exchanges sodium (a soft mineral) for magnesium and calcium (hard minerals), DI actually reduces the total dissolved solids in water, draining them from the system and eliminating them from the final product. DI or R/O type water systems should be considered for any application requiring clean, trouble free water to reduce long term maintenance. All stainless steel wetted parts required with DI water

Reverse Osmosis Water Purification: R/O. is another complete method which separates unwanted materials from the water supply. The separation is achieved by pumping the plant water through a specialized membrane at high pressure which rejects the contaminants and allows the water molecules to pass. Purified water collects downstream to be used by the fog system & rejected contaminants are flushed to drain by a self-cleaning action. The R/O process will remove the following from your typical water supply:

Suspended Solids (rust, pipe scale) approx. 100%  Bacteria and Algae approx. 100%  Dissolved Solids approx. 97%

All stainless steel wetted parts may be required with R/O water.

Note: Reverse Osmosis (R/O) water is generally known to be “aggressive” but is mistakenly understood to be “corrosive”. R/O water is typically less conductive than tap water. Hence, R/O water slows the galvanic corrosion process and is, therefore, less corrosive than tap water. However, R/O water acts as a better solvent.

When copper pipes corrode, they form oxides on the pipe walls which in some cases plugs and seals any pin holes that may be present.If R/O water is introduced into a pipe that has been in service for a period of time, the R/O water will dissolve the oxides that have formed on the pipe and sometimes will unplug pin holes causing a leak. Here, R/O water caused a leak not by corroding the pipe, but rather, by unclogging existing holes. Copper pipes used with R/O water from the start may actually see an increased service life due to a slower corrosion rate.