The Q&A Archives: Algae on Pond

Question: Why is my new pond all of a sudden covered in algae and looking thick and murky? How can I get rid of it?

Answer: Algae is actually a sign of a healthy pond, and it's very normal for new ponds to host an algal bloom. But it can get invasive and most people consider it unsightly. "Good bacteria" may sound like a misnomer, but adding specific bacteria to the pond's water will help control algae. Pond owners can purchase beneficial bacteria in either a dry or liquid form from pond suppliers, and pour it into the pond. The bacteria requires the same nutrients as the algae, so it basically out competes the algae by consuming its food supply and ultimately starving it. Chlorinated water doesn't contain this bacteria and although it will occur naturally over time, the process is often too slow in an artificial environment. Add beneficial bacteria to your pond about once a month in summer; twice a month when temperatures are cooler.

A biological filter, sometimes called a biological clarifier, provides a location where bacteria can easily colonize. The filter keeps algae away and has moving water, which provides an oxygen source for the bacteria. Used together, the filter and the beneficial bacteria will help keep your pond's water clean and clear.

The bacteria go dormant from late fall to early spring when temperatures cool. Be patient because it won't work overnight. If the algae's appearance bothers you, scuff up a rod, such as a broom handle, with sandpaper and then using it to "twirl" up the algae like spaghetti. Add the nitrogen-rich algae to your compost heap and it will really heat up!

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