What does it do? A natural mineral water neutralizer.

A natural mineral water neutralizer is a safe and simple method to increase the pH of acidic water.  The tank contains a mineral called calcite which is granulated marble, and in extreme cases, another mineral called magnesium oxide is blended in.  When water passes through the calcite, if it is acidic (a pH reading of below 7), the calcite dissolves into the water and raises the pH to 7.  On a yearly basis (for most installations) a technician will need to add more calcite to the filter to replace what has dissolved.

There are many in my industry who will claim that some very acidic water can only be treated with harsh chemicals such as sodium hydroxide (lye) or potassium hydroxide (almost as bad as lye) or some other caustic substance.  They do not know what they are doing.  If they tell you that the job can not be done without these chemicals, please kick them out of your home, because what they are proposing is to inject skin destroying chemicals into your water to an extent that certain malfunctions could cause anyone bathing in or drinking that water to be severely injured.  Anyone proposing the use of these chemicals can not truly have the customer's best interests in mind.  Do not allow chemical injection systems utilizing caustics to be installed in your home.

They will still insist that chemicals are the way to go, but anyone who says that has been too lazy or set in their ways to discover why they think the natural ways don't work.  It is simple.  They have used inferior materials in the neutralizers they have used, or they had no idea of how to add magnesium oxide to the system, and mainly, it is a combination of the two.

First, the only calcite that should be used is one of the quality of Imerys calcite, a pure white crushed Georgia marble.  Most newbies or un-inquisitive old timers fall into the trap of using whatever "calcite" the local plumbing supply house carries.  Unfortunately, what most plumbing supply houses carry is not calcite but instead LIMESTONE.  Limestone is up to 15% non dissolvable solids, which, as you would guess, reduces the effectiveness of a NEW system by 15%.  And as the years go by and new limestone is added on top of the leftovers, you can get to a point where 50% or more of what is in the tank is no longer an active pH raiser, but simply granulated rock.  And with neutralizers being installed in basements, it is unlikely that your technician is going to want to single handedly drag the four or six hundred pound beast out of the home, tip out all of the old limestone, and refill it with fresh product.  Or, if the technician is adventerous, he will load gobs of magnesium oxide on top of the useless limestone, instead of blending it with the calcite like it needs, and that mineral ends up as a solid ball so hard that water does not penetrate it and dissolve it, nor can it be removed from the tank if the technician decides to rebed the system.  So they learn, calcite neutralizers don't work (which is true the way they use them).

And now, why have we gotten to this rant today?  I have spent the last two weeks recovering from lye burns on my knees.  I knelt in a crawl space to help a customer repair a feed pump and the previous contractor spilled sodium hydroxide on the floor in a way that it could not be seen.  What if it was the customer?  His child?  It could have been much worse since I was able to figure out what was happening to me and remove my clothes and rinse off my knees before it got worse and someone else may not have figured it out.  

Here is an example of a high quality backwashing calcite neutralizer sold through my company and built by Danbury Manufacturing Inc. under the Blue Frog brand.

It also does double duty as a backwashing sediment filter.

cleanwaterman.com