Blanket weed is a symptom of too much
nutrient in ponds, often caused by overstocking of fish; over-feeding of fish;
frequent topping up with nitrate-rich tap water; leaking of nutrients from
potted pond plants or seepage of fertilisers from adjacent land.
There are several options for control of
blanket weed in ponds. - Ultrasound, Barley Straw, or nutrient reducing
bacterial brews.
The ES-10 and ES-25 for
control of algae in ponds of up to 40 square metres has proved very successful.
The unit not only controls blanket weed, but also greed water, fungi and
bacteria , improving the overall health of fish in the pond. There are no
effects on other wildlife, and bats are unaffected because the unit is below the
water surface.
Details on the use of
Barley Straw, which releases compounds that
inhibit algal growth and promote invertebrate grazing, or reduction of nutrients
can be found elsewhere on this site.
Nutrient reduction in ponds can be
achieved by either reducing nitrates using
Viresco, or by reducing phosphates adding sachets of
ProCrystal.
Viresco is a concentrated bacterial
mixture that needs to be activated before adding it to the pond, by aerating it
in a bucket of pond water for at least 2 hours and up to 8 hours. It
usually only needs one application per season and like all bacterial products it
cannot be overdosed. It can be used in any size of pond.
ProCrystal comes in 450g sachets that
treat 100 square metres each. Again it cannot be overdosed and can be
added to ponds of between 25 and 150 square metres. It comes in a water
soluble sachet that is just thrown onto the surface of the blanket weed. You may
need to retreat every 30 days at this rate until the algae disappears, and then
go back to a maintenance dose rate of one sachet per 300 square metres, or one
sachet every 3 months, whichever is easier for your pond.
