Water softeners

Not long after I first moved into a house from an apartment, I woke in the night to the sound of rushing water from the basement.

Groggily, I investigated, visions of finding all my boxes of junk afloat dancing in my sleep-fogged brain, only to discover that all that noise came from a cabinet-sized device I had never had to deal with before: a water softener.

The concept of water softening puzzled me as a kid (actually, it puzzled me right up until I started this column). I thought “hard” water came in cubes, while “soft” water came in nice splashy puddles. All it took to soften even the hardest water was a little heat.

I still think that makes more sense than the truth, which is that water is called “hard” when it has lots of certain minerals dissolved in it.

In nature, all water contains dissolved inorganic and organic substances, because water dissolves practically everything. Every litre of most rivers contains between 20 and 2,000 milligrams of dissolved solids, usually calcium, magnesium, sodium, potassium, sulfate, chloride, carbonate, bicarbonate or silica. Which of these are present depends on the kind of rocks in the region, while their concentration depends largely on climate; the more water that evaporates, the higher the concentration of solids in the remaining water.

Only four of these substances are considered “hardness” minerals: calcium, magnesium, iron and manganese. Water is considered hard if it contains more than 120 milligrams per litre (parts per million) of any of them.

(Actually, water hardness has its own measurement system, “grains per gallon,” or just “grains.” One grain is equivalent to 17.1 milligrams per litre, so water with 120 milligrams per litre of hardness minerals in it is said to have seven grains of hardness.)

Regina’s water (and just about everybody else’s on the prairies) is always hard, and sometimes it’s very, very hard. Most of Regina’s water comes from Buffalo Pound Lake, which generally has about 14 to 20 grains of hardness. Sometimes, though, well water supplements the supply, which can push the hardness level all the way to 60 grains. (After all, what else has well water got to do down there but dissolve minerals?)

The hardness minerals in our water are calcium and magnesium (a bit more calcium than magnesium). Considering what people pay for mineral water, you might think that hardness would be desirable, but instead, people are always trying to get rid of it.

That’s because hard water forms scale — a deposit of carbonate salts — on the inner surfaces of boilers, cooking utensils, and pipes that carry hot water or steam. As well, the mineral salts cause the fatty acids in soap to form a scum or, as one encyclopedia put it, a “gelatinous curd” (sounds like something from a Stephen King book). Since soap’s fatty acids are what make it lather, it takes more soap to wash with hard water than with soft.

Although some of the minerals in hard water are beneficial to the body, like calcium, their concentration in even the hardest water is too small to help. (Besodes. if you’re counting on your drinking water for your calcium, I suggest a hard look at your diet!)

Given that hard water is undesirable, how do you get rid of it? For more than 70 years, the answer has been a water softener.

In most softeners, hard water flows through a tank filled with “resin,” tiny polystyrene beads like microscopic golf balls. Millions of sodium ions coat each bead, and as hard water flows over the beads it exchanges its calcium and magnesium for their sodium.

After a while the resin becomes saturated with hardness ions, quits working, and has to be regenerated: the softener reverses its flow, and salt water from a brine tank flows through the resin. The resin gives up its hardness ions for a new coating of sodium ions, and the hardness minerals flow down the drain. This noisy process is what woke me.

Softeners typically flush 30 to 50 litres of water down the drain for every 1,000 litres softened. They also consume half a kilogram of salt per 3,600 to 5,000 grains of hardness removed (two to three kilograms per regeneration), which means softened water contains extra sodium (about 100 milligrams per litre if the water is moderately hard), which people on sodium-restricted diets may want to avoid, and others claim tastes funny. This is why houses with softeners usually also have a tap providing unsoftened water.

My water softener and I are on much better terms now. I keep it fed with salt, and it no longer wakes me in the night.

Now if I could just get that darn hard-water tap to dispense ice cubes …

Permanent link to this article: https://edwardwillett.com/1992/09/water-softeners/

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Easy AdSense Pro by Unreal