How to Use Potassium Permanganate in Treating Water

A common chemical oxidant, potassium permanganate (KMnO4) has seen extensive use in water treatment. It is reactive with metals as well as being effective against a number of microorganisms such as algae, bacteria, fungi and viruses. The crystals of permanganate are a strong oxidizer, and when solid, can cause eye injury, skin and lung irritation. Dissolving the KMnO4 crystals in water minimizes this risk.

Things You'll Need

• Safety goggles
• Dust mask
• Gloves
• Sponge

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Instructions

Municipal Water Treatment

• 1

  Treat water with potassium permanganate as an alternative to first-stage chlorination. According to the EPA, a concentrated solution of 1 percent to 4 percent potassium permanganate removes the metals iron and manganese as well as decomposing plant matter. This helps defeat taste and odor issues, removing the unpleasant earthy and musty smells.

• 2

  Reduce disinfection byproducts (DBP) with potassium permanganate. DBP occur when disinfecting chlorine reacts with natural water compounds such as decomposing plants, and they can be harmful to human health. Removing these natural compounds with permanganate before the chlorination step ensures that the water is safer for residents.

• 3

  Control creatures such as Asiatic clams and zebra mussels using potassium permanganate. These nuisance organisms can clog fresh water intake pipes of water treatment plants.

Fish Tank Water Treatment

• 4

  Koi infected with parasites can be treated with potassium permanganate.

  Turn off the filter and sponge down the walls of the tank to remove as much algae as possible. Potassium permanganate treatment causes metals to precipitate out of the water, clogging the filter if it is left on. It also oxidizes algae before it destroys bacteria and parasites--you will waste permanganate if the tank is slimy.

• 5

  Calculate how much dry potassium permanganate you require for the fish tank. You will need 1/8 teaspoon of permanganate per 125 gallons of tank water for a full-strength solution. A half-strength solution requires 1/16 teaspoon of potassium permanganate per 125 gallons of water.

• 6

  Dissolve the dry potassium permanganate in a bucket of water. Wear safety glasses, gloves and a dust mask as the crystal permanganate is very irritating to skin. Add the pink potassium permanganate solution to the tank water. The tank water will also turn pink.

• 7

  Wait 45 minutes. If the pink color disappears from the tank, add a half-strength potassium permanganate solution. Wait two more hours, and if the pink color again disappears, dose one more time with a half-strength permanganate solution.

• 8

  Wait 10 hours. Replace one third of the tank water with fresh water and turn the filter back on. Repeat the entire process in seven days to control fish parasites such as ick, flukes, Chilodonella or Apiosoma.