Scaly Monsters

If calling this blog Bad Plumbing isn't a blatant enough attempt at capitalising on Ben Goldacre's well-established and successful "Bad Science" brand to precipitate an attack of the lawyers, then trespassing on his turf with a health-related story must surely provoke the good doctor beyond endurance.

This is limescale:

Lechuguilla Cave, New Mexico
photograph by Derek Lee, licensed CC BY-SA 3.0

No self-respecting cave should be without some, but you don't want it swilling around as white flakes in your kettle, clogging up your showerhead, destroying your electric shower or damaging your combi boiler. Though apart from that it probably doesn't do you any harm - and may even be good for your heart - though possibly not good for your skin.

These are scale inhibitors:

They come in a variety of technologies - magnetic, electromagnetic, electrolytic and phosphor-dosing - the plumbing-world equivalents of crystal healing, acupuncture, homeopathy and science-based medicine. In other words most of them may look and sound impressive but there's precious little evidence that they actually work, except for one type which does: phosphor dosing.

Here are some phosphor-dosing scale inhibitors:

These all have a container of "polyphosphate" material - as a powder, granules of various sizes or lumps the size of small marbles. Some of this material dissolves into the water as it passes and - through mechanisms which weren't part of the Chemistry syllabus when RP was at school - prevents the Calcium Bicarbonate in hard water from changing to Calcium Carbonate and precipitating out as Limescale when the water is heated. (Executive summary: it just works.)

These phosphor-dosing devices come in various shapes and sizes, at prices generally between £50 and £100.

And this is a typical water softener:

These work on a completely different principle to scale inhibitors, swapping the Calcium bit of Calcium Bicarbonate for Sodium. Sodium Bicarbonate ("bicarb" to you cooks) doesn't turn into solid clag when it's heated and even when it dries up on surfaces (such as the tiles around your shower, and on taps etc) it dissolves off again easily. But water softeners cost around £500, and you have to keep feeding them large bags of salt which can get expensive.

And this is NoCalc.

Technically it's a phosphate-dosing scale inhibitor: it adds a bit of polyphosphate to the water. However by a clever application of advanced marketing technology it has become a scale inhibitor. And costs £250.
Click on any of the pages from the brochure above to see a full-size image, or here for a PDF version of their (more recent) brochure.


As we can see this device offers remarkable benefits:

Not least of these is - we learn - that NoCalc "prevents skin irritations, eczema and psoriasis"! This is surely such wonderful news for the millions of eczema sufferers alone that one hopes the NoCalc factories are capable of producing these miraculous devices at sufficient rate that those afflicted by this distressing condition (and their parents - eczema particularly affects small children) do not have to wait long for relief from their problems. Once they've found the paltry two hundred and fifty-odd quid for one, of course.

And of course extending the life of one's dishwasher, washing machine and central heating boiler, reducing energy bills (by at least the £249.99 purchase cost of the NoCalc) and using less than a third of one's normal soap and cleaning products is not to be sniffed at either.

Sadly, however, the brilliant feat of literary engineering that has endowed this humble device with such unparalleled benefits for humankind fares badly when exposed to the agent known as ASA.