Re: Is changing icemaker water filters a scam?
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Originally Posted by Dennis Nicholls
Philip,
So filters don't remove hard-water minerals? What good are they then?
Boise city water comes from the Boise river upstream from town. The water is hard here but the water is softer than it would be drawn from wells.
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Filtration, as provided in a refrigerator cartridge, will not remove hard-water minerals. However, the hard water minerals may cling to the particulate matter in the water and when you remove the matter it may look like lime scale (or lime slime) when you open the filter. The amount removed in the filter will not change the "hardness" of the water.
Water softening is done in one of three main ways:
1. It takes raising the pH of the water and precipitating out the hardness chemicals (mainly magnesium and calcium carbonates and hydroxides) which undergo chemical changes at high pH. The water plant then lowers then pH to stabilize the water.
2. Exchaning of the calcium and magnesium for sodium or potassium using an ion exchange resin (house water softener) that you regenerate.
3. Reverse osmosis - which is basically a type of "high-pressure filtering" that can remove the minerals.
You can also use eloctrodialysis or boil the water and collect and recondense the steam, but these are extremely high energy or impractical ways.
A refrigerator water filter will remove large particulate matter, and if charcoal based, may remove disinfection chemicals (chlorine and chloramines).
If you have a charcoal based filter that removes the disinfection chemicals you should never fill a pitcher and leave it settting around for a long time as you have now removed the chemicals that inactivate organisms that could make you sick.
Sorry about the long response - I am a water supply engineer with 22 years experience who designs municipal treatment, pumping, and distribution systems.
PS - even though tap water is very good in my home community and just as "safe" as bottled water, I prefer the filtered water from my refrigerator over straight tap water. The filter does remove some particulates and chemicals that make the water taste not quite as good.