6679 Highway 15
Seeleys Bay, ON K0H 2N0

Last month, we discussed the role of wollastonite in managing phosphorus.

That prompted some Ontario residents to begin experimenting with adding wollastonite to pond water. With the recent heat and drought across much of the province, ponds and small bodies of water on farms, golf courses, and rural properties are especially subject to excessive algal growth – an unpleasant and unhealthy condition, as these photos demonstrate.

Pond waters choked with algae before treatment with wollastonite.

This algae growth is caused by excess nutrients in the water (eutrophication) – primarily phosphorus and nitrogen. When wollastonite is added to the water, the calcium silicate molecules begin to dissolve, creating opportunities for the excess phosphorus in the water to bond with the calcium to create stable molecules of a substances called apatite.

Without excess phosphorus, the algae doesn’t proliferate, restoring balance and clear water. As an added bonus, the silicon ions help promote healthy plant growth – many aquatic and semi-aquatic plant species thrive on high levels of silicon!

When this theory was put to the test the results were remarkable. Only three days after the addition of wollastonite, the algae levels were significantly lower. The effects have been long-term, too – while other, untreated ponds on the property are increasingly clogged with algae, the treated pond remains relatively clear.  In this case, the wollastonite was hand broadcast into the pond from the shoreline at a rate of 68kg per one acre pond with an average depth of 3 metres.

Three days after treatment with wollastonite, the pond is visibly cleaner.

Three weeks after wollastonite application. (Source – Fairgreen Sod Farm, Markham, Ontario)

Other businesses are starting to take note. A livestock farmer is keeping his water supply free from algae by adding wollastonite to his herd’s water troughs. A golf course has ordered large quanitities of wollastonite to treat their water features.

Wollastonite: a white mineral for a green world…and blue water!