In 1933 Calgon Incorporated of Pittsburgh introduced its flagship product, appropriately named “Calgon.” The name was derived from the phrase “calcium gone,” which was an accurate description of what the product was designed to do, namely soften water. Hard water has a high content of dissolved minerals, mostly salts of calcium and magnesium. Various problems ensue when the concentration of these is greater than about 120 mg per liter. Unlike the sodium salts of fatty acids that are the basis of soaps, their calcium and magnesium salts are insoluble, resulting in the classic bath tub ring. Although detergents do not form precipitates with hard water minerals, they do form soluble complexes that reduce cleaning efficacy.
Another major problem is the conversion of dissolved calcium and magnesium bicarbonate to insoluble calcium and magnesium carbonate when the water is heated. These insoluble salts form a scale that can clog pipes, deposit on clothes and in theory, lead to early breakdown of washing machines. Softeners added to water either cause the calcium and magnesium to precipitate as salts that are easily rinsed away, or sequester the calcium and magnesium ions as soluble complexes preventing them from reacting with soap or forming deposits.
The original version of Calgon consisted of sodium hexametaphosphate, a chemical that would sequester calcium and make it seem as if it really were not there. The calcium appeared to be gone! Advertising emphasized the ability of Calgon water softener to improve the appearance of laundry. When television invaded the American scene, Calgon was ready with clever ads. In a classic, a lady asks an obviously Asian laundry shop owner how he gets the shirts so clean. “Ancient Chinese Secret,” is the answer, delivered with the appropriate accent. The “secret” is exposed when the owner’s wife sticks her head in and shouts, “we need more Calgon!”Â
By this time the water softener had been joined by a line of Calgon bath salts and bath oils. These also contained sodium hexametaphosphate to soften the water but also incorporated magnesium sulphate, or “Epsom salts.” This combo gives the water a more slippery feel and can also soften calloused skin. Calgon bath oils also were popular, basically consisting of coconut oil that would leave a silky deposit on the skin. Ingenious advertising slogans promoted these products. “Love the skin you’re in.” “Lose yourself in luxury.” And the classic, “Let Calgon take you away.”Â
In 1968, Calgon was acquired by Merck and eventually broken up and sold off to a number of companies together with the right to use the name Calgon. Today, there are various bath products, body mists, creams, and beauty bars that feature the Calgon brand. And water softeners are still with us, although the original formulation has been altered because the environmental consequences of phosphate use have come to light since their introduction back in the 1930s. Since phosphorus is an essential plant nutrient, an abundance of phosphates in natural waters can lead to excessive growth of plants and algae, which upon their death decompose and use up some of the water’s dissolved oxygen. This can have dramatic effects on aquatic life.Â
Several versions of Calgon water softeners are now available, conforming to local laws about how much phosphate content is allowed. In most cases the active ingredients are sodium sesquicarbonate and various polymers that fall under the umbrella of “polycarboxylates.” These are either polymers of acrylic acid or copolymers of acrylic and maleic acids. They do the same job as the phosphates, namely bind minerals in solution, but without the environmental consequences of the phosphates. The Canadian version still contains a small amount of pentasodium triphosphate, while the U.S. product uses a mix of sodium sesquicarbonate and sodium citrate, yet another polycarboxylate, to soften water. Advertising emphasizes that less detergent can be used if the water is appropriately softened because the complexed dissolved minerals do not interfere with the activity of the detergent.
In Europe, Calgon’s emphasis is not on softening water, but rather on the product’s role as a saviour for washing machines. The claim is that scale buildup inside machines shortens lifespan, and addition of a water softener to each load of laundry can keep the machines from premature death. Whether or not this is so is controversial. The British consumer organization Which? addressed this issue by simulating three years worth of washing, and while it found that indeed there was a decrease in the amount of scum that built up, there was no difference in the way the machine performed whether Calgon was used or not. In fact, Which? researchers calculated that the amount of money spent by adding a water softener to every load would be enough to buy a new machine when needed, even if the scale deposits shortened the life of a machine, which apparently is not the case. Many consumers were irritated by this finding, thinking that they may have been throwing their money down the drain. Calgon could have advised them to take a comforting bath using Calgon bath salts and bath beads.
And how do you clean that bathtub ring? Just use some chemistry. Oxalic acid will complex with minerals and make them soluble. It is commercially available as “Zud.” A paste of tartaric acid (cream of tartar) will also work. So will citric acid. But you have to combine these with a bit of elbow grease!
