Throughout the winter, organic matter is being added to your pond. This includes twigs, leaves, bird droppings, undigested fish food and just about anything that can end up in the pond. As this organic matter breaks down it produces ammonia, phosphorous and hydrogen sulphide, which are all sources of food for algae.
This is why it’s so common for ponds to be green when people go back to them in spring. If left untreated it can take all summer long to get them back to a healthy colour, and then winter’s coming round again.
There are products on the market that will clear your pond almost instantaneously. These products work by clumping the organic matter together and sinking it to the bottom of the pond floor, which gives the immediate aesthetic results but will come back to haunt you.
It’s far more beneficial to use a bacterial treatment that will actually digest the organic matter and therefore solve the problem. For the first treatments in spring we recommend using a treatment specifically aimed at pond sludge as it will make reducing any further problems – like green water – much quicker.