Do you really know what hard water is?

I am a registered CEU provider with the American Society of Plumbing Engineers (ASPE) on the subject of “Physical Water Conditioning. One of my early slides is this one:

Most people, and I mean at least 95%, get the answer wrong – even professional water softener suppliers – and I shall save their blushes by not naming them get it wrong. So the correct answer is “C,” but most people answer “B” – why is that?

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It is the dissolved form of Calcium and Calcium Ions that are the cause of hard water, and they have two unusual properties. They are less soluble in hot water than in cold water – the opposite of sugar and salt. Secondly, when they come out of solution, they can’t crystallize on their own; they have to crystallize onto something else. They normally stick to surfaces such as pipes and heat exchangers as “scale.” 

Normal softening of water using “ion exchange” takes the Calcium out of the water by substituting Sodium. The Sodium comes from Sodium Chloride, salt, that is used to soak the media. It is a very effective way of removing Calcium Ions and softening the water.

An alternative approach would be to remove the Bicarbonate, converting the Calcium Ions to Calcium Carbonate. This is exactly what happens to some of the ions when the water is heated. The problem is that you then have a scale problem, and how do you get most or all of those ions to come out of the solution anyway?

If you could fix it so none of the Calcium Carbonate sticks to the surfaces and all of the ions precipitate, then you would have soft water and no scale to worry about.  That is exactly what a good Physical Water Conditioner such as Aqua-Rex can do. 

Aqua-Rex generates an alternative surface, a nucleation seed, in the water, so the scale starts forming on the nucleation seed instead of the surfaces. Once you get one crystal of calcium carbonate formed in suspension in the water, it attracts more scale to it and grows from a sub-microscopic particle eventually to a suspended powder like chalk dust.

The existence of these growing nucleation seeds encourages even more Calcium ions to precipitate – it becomes a very “scale-friendly” environment, so the water becomes softer and softer.

The point is that the water is much softer but still contains the same amount of Calcium, now in suspension as Calcium Carbonate instead of in the dissolved form, Calcium Bicarbonate. 

“Well, it only softens the hot water,” did someone say? Yes, but most people bathe, shower, and wash their clothes in hot water, and many commercial water softeners are only installed on the cold supply to water heaters; the rest of the cold supply remains untreated.

The problem comes when trying to measure how soft the water actually is. Normal methods of measuring hard water do not measure the hardness of the water at all. They measure “Total Hardness,” which is both dissolved and suspended Calcium. They are incapable of measuring the Calcium Ions on their own to give a true measure of softness. What you need is a Calcium Ion- Selective Electrode (Calcium ISE) and a laboratory or similar to use it. It’s not something you can easily carry around and set up in a client’s kitchen!

A simpler but less precise way to measure hardness is to filter out the particulate using a fine filter such as 0.45 microns and measure the total calcium remaining. Some of this will be finer particulate and not in solution, but it gives a good indication of how much softer the water would be.

For many years, the Water Quality Association (WQA) and water treatment professionals have agreed that PWC’s can reduce scale but claimed they don’t soften the water as they can’t “remove the calcium”. What Aqua-Rex, or its parent company Lifescience Products, has clearly demonstrated in many independent third-party laboratory tests is that the Calcium Ions are removed by converting them to Calcium Carbonate. The water containing Calcium Carbonate in suspension is soft water according to the US Geological Survey definition of soft water being less than 60 ppm Calcium Carbonate Equivalent. The true measure of softness has to be whether the soap lathers better, the water is softer on the hair and skin, and in this respect, Aqua-Rex passes the user test.

Ironically, the best result that one can look for when using traditional “Hardness Tests” is that there is no reduction in “hardness” at all. None of the Calcium should be left as scale in the water heater, it should all be in suspension so there is no change in Total Hardness.

So what do you say to a homeowner who asks, “How can I tell if it is working?”. Look for a reduction of scaling on shower heads, countertops, and faucets, and feel the difference when you take a shower and wash your hair. That is the true user test and is the way to judge whether the product works well enough for you.