I am considering switching to a polyphosphate-containing water filter for my refrigerator ice maker/water dispenser. Currently, I use softened water to prevent calcium build-up in the ice maker/refrigerator, but would rather not in order to reduce my sodium intake.

So, would polyphosphates greatly reduce the calcium buildup in my ice maker? (I'm worried about the low temperatures affecting their effectiveness). Or does it work only in hot water boilers? Should I use some other chemical based on my water chemistry? Or is it junk science?

My water pH is 7.4-7.7, with about 400 ppm of CaCo3 (in West Lafayette, IN).


As an alternative option, you can use Potassium Chloride instead of salt in your softener.

(On a side note, by my math two liters should only have under half a gram of sodium at that hardness)

  • You're right. I screwed up the arithmetic.
    – Pigrew
    Sep 11 '14 at 21:26
  • SDS (sodium lauryl sulfate), as found in shampoo and dish washing deyergents forms an insoluble potassium salt, the sodium salt is soluble, so you might end up with a soap scum problem. Mar 26 '16 at 18:42

We solved this problem by installing a small reverse osmosis filter for the ice maker as well as for cooking and drinking. Such a filter will soften the water without adding any chemicals at all.

The only downside to this is expense. You will have to periodically change filter cartridges. That isn't outrageously expensive, but certainly more than salt.

One other downside, I suppose, is that here is a fair amount of water wasted by the filter. If you are on a reliable well, the wasted water may not matter to you. Also, if you really need to, you can recover that waste water for other uses. We aren't on a well, and our water consumption for ice, cooking and drinking is dwarfed by the rest of our consumption for toilets, showers and laundry (i.e. our water bill didn't go up). So, I personally don't care about the "wasted" water.

The Costco local to us had a system for a couple hundred that worked well.

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