In my last column, I wrote rather extensively about green sand iron filters in domestic use. If you got the feeling after reading this column that these units were really not very successful and, in fact, a pain to regenerate, you’re right. The manufacturers in the water conditioning industry had long realized that a successful filter had to get the iron from solution, or invisible, to suspension, or visible, iron. How to do this seemed to baffle everyone for a long time. We had the green sand filters which, if properly maintained (and they usually were not), worked well, and not much else.
One of the first attempts I experienced as a non-green sand filter was one that used a catalyst bed. When it came out, this was supposed to be “the” way to convert iron to a filterable form. I think I only sold one of these units, and it was not very effective. As I remember, this type of filter was only on the market for a very short time. About this time, pretty much the whole industry — that is, manufacturers, suppliers and installers — figured out that we had an unlimited supply of the oxidizer needed to change clear water iron to particle iron. This material, of course, is oxygen, which is part of the air we breathe. I realized this myself, not with a filter but with a Jacuzzi bathtub.