Hardness in Drinking Water

Hardness is not a regulated contaminant or water quality, but rather a subjective characteristic of water as it relates to washing, laundering, and its use in industrial cooling. Hard waters are said to be those that require large amounts of soaps or detergents in order to form a lather and be effective as a cleaning agent. Hard waters also tend to be scale-forming when used as coolant in heat exchangers.

Chemically, hardness is caused by a group of several significant divalent cations naturally found in water and hardness varies considerably depending on the geology of a region. In general, surface waters are softer than groundwaters. The significant hardness-causing divalent cations include: calcium, magnesium, strontium, iron and manganese.


Tonka Water Hardness Removal Technologies

Tonka Water offers pilot testing to optimize an existing plant or to assist in the design of a new plant. 

Ion Exchange Systems

Ion Exchange softening by Tonka Water’s ion exchange systems offer pressurized treatment and controls to achieve precise blended hardness goals. In groundwater supplies with high hardness and the presence of iron and manganese, pre-treatment of the iron and manganese is required. Depending on the application, any one of Tonka Water’s iron and manganese technologies can be employed as pre-treatment.

Ion Exchange Systems


The Pur-IX™ system features the lowest brine consumption in the industry using unique continuous ion exchange technology. Continuously regenerated without affecting treated water production, it operates up to 3000 GPM on a single multi-port valve, features virtually no maintenance and seamlessly operates without interruption for regeneration.

Pur-IX Ion Exchange System

Flux RO/NF Membranes

Tonka Water’s Flux RO/NF™  membrane treatment uses spiral-wound membranes to “filter” or exclude the dissolved divalent cations, under reverse osmosis pressure. Tonka Water Flux RO/NF™ treatment systems can soften even the hardest waters through our innovative technology; we use the latest in membrane treatment, all packaged in a factory assembled compact treatment system, complete with the Tonka Water system guarantee.

Flux NF/RO Membrane System

Lime and Lime-soda ash softening

Lime and lime-soda ash softening is the physical/chemical process using mixing, coagulation, flocculation, settling and filtration for precipitating and removal of hardness causing compounds. Tonka Water offers several solutions for lime and lime-soda softening.

  • RotaClear™ –  an ideal product for physical/chemical softening in a single process unit – at the lowest operating cost.
  • TriClear™ –  solids contact systems can be an integral part of any lime softening system, using upflow propeller mixing, flocculation and settling in a single unit.
  • Spira-Clear™ – pelletized softening system is a unique upflow clarifier using pH adjustment and catalytic softening.

Contact us with your water treatment needs

Each plant has different design parameters involving varying water composition. Because each hardness situation is unique, we offer pilot testing to optimize an existing plant or to assist in the design of a new plant. Call your Tonka Water Representative for more information on hardness removal or any other water treatment needs you may have.

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