We recently heard from 'Lia' who asked, " Hi, we are aware that our spring water develops ferric iron upon contact with the oxygen in the air although we do need a kit to make another general test. The problem is getting it out as it only develops once in the pool - originally we thought of a filter of some sort between spring and pool but the stuff hasn We know manganese greensand can be used to filter it out having treated the water with chlorine but we don't know how to do this - can it be used in the normal pool filter system instead of silica sand? If you are not the people to ask perhaps you can direct me to a useful source? I will order the test kit later today.  Ps There is a lot of the ferric iron; it covers the bottom of a small pool!"


For those unfamiliar with the problem excess iron in pool water may cause...

  • In high enough concentrations it will make pool water look VERY uninviting because it may give the water a brown, dark and/or otherwise unpleasant appearance.
  • Iron may form sediments and stains when chlorine or other oxidizers get added to the pool water... and in the case of staining some of the iron stains may take on a permanent and certainly unwanted nature.

Does iron pose a health risk?  Not really, but again, iron in pool water may take on a really unpleasant appearance due to discoloration and the formation of sediment, solids and/or gross looking stains on pool surfaces.

To answer Lia's question directly, one should NOT attempt to replace traditional pool filter sand with other filtration substances (like Greensand which gets used to filter out unwanted water contaminants such as  ironhydrogen sulfide and/or manganese).

Since Lia mentioned ferric iron covering the bottom of her pool, it sounds like whatever filtration option she chooses should include a  sediment pre-filter.  Taking out 'solids' (like ferric iron) before water hits the main filter helps to extend main filter life and efficiency.

We found additional recommendations for iron reduction and iron removal on the FilterWater.Com web site:

First Things First:  How Much Iron Does the Water Source Contain?

As with any water contamination situation, the removal/reduction method depends greatly upon the concentration and nature of the contaminant.  Always TEST YOUR WATER before investing in  a water filtration system... or run the risk of purchasing and installing the wrong products!