whidbeywaterfilters

Tannin

Tannin

  • What is tannin?
    Tea is tannic acid. It causes water to yellow. In wooded areas, when it rains the water steeps in the leaves on the ground and creates tannic acid, which seeps into the ground and enters the well water. Tannin is harmless; it simply colors the water. If iron is also present in the water, tannin will combine with the iron, creating another element that prevents oxidized iron from being totally removed during filtration, so that some iron will exit the filter along with the tannin. For this reason, it is helpful to remove the tannin.
  • How to detect if tannin is present.
    A quick and simple way to determine if there is tannin present in the water is to fill a clean white five-gallon bucket with water and to examine the water in the daylight. The water should look crystal-0clear. If the water has a slight yellow or green hue, most likely tannin is present. A fancier way to tell is to request a water test from a professional lab.
  • Ways to eliminate tannin.
    There are three ways to remove tannin.
    • Bleach it out with an injector, using either chlorine or hydrogen peroxide.
    • Filter it out with a very expensive special media that must be replaced annually.
    • Add a special tannin resin to a water softener. The formula is 10 pounds of resin for every one part of tannin. Softening resin does not need to be present; there could be simply tannin resin in the tank, but generally if the water is hard anyway, including both resins in the same tank is an efficient combination. Salt must be replenished in the brine tank every week or two in order to sustain the ionization process. Although tannin resin is quite expensive, as long as the salt level is maintained, it will last many years.
    • A fourth option is simply to live with the tannin and not remove it at all.
  • Tannin removal
    ECOsmarte opts for installing an injector pump. Hydrogen peroxide is generally more effective than chlorine. The injection point is installed after the titanium chamber and before the retention tank. If tannin is indeed present, ECOsmarte will include a injector pump and tank at no additional charge.
      • To prevent the injector pump from running constantly, a flow switch is necessary; it activates the injector pump only when water is flowing.  This switch must be purchased separately and can be ordered on-line.
      • Note also that tannin is not included in the water test, so a tannin test must be requested when the original test samples are sent to the lab.