(Template Assisted Crystallization)
There are Different Forms of Hardness in Water
• Calcium and Magnesium Bicarbonate- This is what is referred to as temporary hardness. Once it is dissolved into water, heating that water can cause it to precipitate and form scale. It has a relatively low solubility.
• Calcium and Magnesium Sulphate/Calcium and Magnesium Chloride- This is what is referred to as permanent hardness. Once it is dissolved into water, heating that water usually does not cause it to precipitate and form scale. It has a higher solubility than temporary hardness. This means the water can keep more of it in solution.
TAC’s Effect on the Different Hardness Types
• Temporary Hardness- TAC converts dissolved temporary hardness ions into microscopic nano-crystals. This prevents the hardness in the water from sticking to the plumbing components as scale inside the plumbing system.
• Permanent Hardness- TAC does not react to form nano- crystals with permanent hardness however that is usually not a concern. This is because permanent hardness is:
1- Not driven to form scale when it is heated
2- Much more soluble than temporary hardness so RO membranes are not affected.
TAC media isn’t sacrificial; it doesn’t dissolve. Media lifecycle is not influenced by the amount of water being treated, or the hard- ness of the water. However, impurities in the water, such as chlorine, over time can degrade the template on the beads. The typical suggested media change-out is three years.
Like a water softener, TAC systems may need to be plumbed behind an effective sediment filter. If not, dirt can accumulate in the media bed, coating the resin beads so that their templates are rendered ineffective.
In areas known for hard water, a TAC system could be an effective solution or at least a key part of a multi-component water treatment system.