Just an observation really ...

Large outdoor pond, nice setup, filters, plants, lotsa life, plenty fish, plenty frogs and other wiggly things.

In summer it's fine, but the water always has that greenish tinge.

But I have noticed with the onset of below 10 degree temps that the water has become brilliantly clear and the full 5ft depth is easily seen .... happens every year.

Do algae, plankton, duckweed etc have a low tollerance to these conditions ? Is it a "death zone" for the little critters ?

This post has been edited by MrWiggly: Oct 31 2008, 01:48 PM

Guests - this sponsored link will vanish when you log-in. Click here to register for free.

It's as much to do with hours of sunlight as temperature, but yes, algae do have annual cycles. It's a bit more complicated than that, particularly in large lakes, because it gets driven by the cycling of nutrients, the competition and succession of different types of algae with different nutrient requirements and the boom and bust of grazing zooplankton as well.