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Lime and Calcium Removal from drinking water: A Side-by-Side Comparison of residential water filters.

Lime (calcium carbonate) and calcium are common minerals found in drinking water, and they can cause various issues such as scale buildup in appliances, decreased water flow, and a bitter taste. To remove these minerals from drinking water, certain residential water filters can be installed. Let's compare two popular types of residential water filters that are effective in removing lime and calcium:

  1. Ion Exchange Water Softener:

    • Mechanism: Ion exchange water softeners use resin beads to attract and remove calcium and magnesium ions from the water, replacing them with sodium ions. This process reduces water hardness and prevents scale buildup. 
    • Pros:
      • Highly effective at removing calcium and lime scale.
      • Extends the lifespan of appliances and plumbing by reducing scale buildup.
      • Improves soap lathering, leading to better cleaning results.
    • Cons:
      • The water may contain higher sodium levels, which could be a concern for individuals on sodium-restricted diets or for those with cardiovascular issues.
      • Regular maintenance is required to replenish the resin beads with salt.
      • It does not remove other contaminants such as heavy metals or chemicals.
      • Higher costs of installation and maintenance than under sink unit.
  2. Reverse Osmosis (RO) System:

    • Mechanism: Reverse osmosis utilizes a semipermeable membrane to remove various contaminants, including calcium, lime, heavy metals, bacteria, and other impurities. The water is forced through the membrane, leaving behind the unwanted substances.
    • Pros:
      • Removes a wide range of contaminants, including lime and calcium.
      • Provides high-quality drinking water with improved taste and odor.
      • Requires minimal maintenance compared to ion exchange systems.
    • Cons:
      • Wastewater is generated during the filtration process, leading to some water wastage.
      • It may have a slower water flow rate compared to other filtration methods.
      • The RO process also removes essential minerals from the water, so remineralization may be necessary for some individuals.

In summary, an ion exchange water softener is specifically designed to tackle lime and calcium scale problems, making it an excellent choice if that is your primary concern. However, it's essential to consider the potential increase in sodium content in the softened water.

On the other hand, a reverse osmosis system provides a more comprehensive water purification solution, removing various contaminants, including lime and calcium. If you want cleaner drinking water with the removal of other impurities as well, an RO system might be the better option.

Ultimately, the best choice depends on your specific water quality, budget, and preferences. It's a good idea to have your water tested before making a decision to understand the exact contaminants present and choose a filter that suits your needs best.

Which water filters inside of RO system remove lime and calcium specifically?

In a typical Reverse Osmosis (RO) system, there are multiple stages of filtration that work together to remove various contaminants, including lime (calcium carbonate) and calcium. These stages typically include:

  1. Sediment Filter:

    • This initial filter traps larger particles like sand, silt, and sediment, protecting the RO membrane from damage and clogging. While it may not specifically target lime and calcium, it helps in improving the overall efficiency of the RO system.
  2. Carbon Filter:

    • The carbon filter, often activated carbon, helps to remove chlorine, chloramines, and some organic compounds that could affect the taste and odor of water. While not specifically targeting lime and calcium, it contributes to improving the overall water quality.
  3. RO Membrane:

    • The RO membrane is the heart of the system, and it effectively removes a wide range of contaminants, including dissolved minerals like calcium and lime. The membrane has extremely tiny pores that allow only water molecules to pass through, leaving behind dissolved solids like calcium, magnesium, sodium, and other impurities.
  4. Post-Filter (Carbon or Mineral Filter):

    • After passing through the RO membrane, some systems have an additional post-filter. This filter helps to further improve the taste and odor of the water by removing any remaining traces of impurities. In some cases, there are specialized mineral filters designed to add back essential minerals to the water, which can help address the concern of demineralization caused by the RO process.

It's important to note that while the RO system effectively removes lime and calcium from the water, it also removes some amount of beneficial minerals because the filters respond to sizes of particles and not the type of particles. Combined with source water contamination level, pressure and time in contact with the filter determines how much of the beneficial minerals get left behind.

Some people prefer remineralization cartridges to add back higher concentration of essential minerals like calcium and magnesium to the water for improved taste and potential health benefits. 

Remember that the effectiveness of an RO system in removing lime and calcium will depend on the specific model and its filtration capabilities. When choosing an RO system, make sure to look for one with a high-quality RO membrane and consider any additional features such as remineralization options, which can help tailor the system to your specific needs.

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