Feeding Polyphosphate to Sequester Iron and Manganese

The recommended feed rate for most situations using ProPoly© is to use one pound (1.5 cups) of ProPoly per 40,000 gallons of water. This produces a 2-parts- per-million phosphate result. Increase the feed rate to 1 lb per 20,000 gallons if iron for water supplies with heavier than normal corrosion and iron.

Pump sizing and feed implications are as follows:

Assume that you have an irrigation system with a feed stream of 17 gallons per minute. If you mix one pound of polyphosphate with one gallon of water for your feeder you have a solution that is approximately 80,000 parts per million phosphate. If you apply these numbers to our pump-size calculator you will find that to achieve a 2 parts per million result you will need a pump that feeds at the rate of 0.6 or so gallons per 24 hours. You could, therefore, mix a pound of ProPoly with 2 gallons of water to produce a 40,000 ppm solution. Your pump would then need to put out about 1.22 gallons per day. Then you could use a 2 gallon per day Stenner pump and set the feed at a bit below the halfway mark.

The essential numbers are:

One pound of ProPoly in a gallon of water makes an 80,000 ppm solution.

One pound of ProPoly in two gallons of water makes a 40,000 ppm solution.

The dosage desired for normal iron and corrosion control is about 2 parts per million. If corrosion is heavy, go as high as 4 ppm.