Algae is a normal part of the ecology of ponds and is a natural reaction to an excess of sunlight, nutrients and water temperature. Algae usually poses no threat to pond inhabitants when controlled/limited, however, it can soon overwhelm a pond when the conditions are right.
Thread algae, string algae and filament algae are common names for a variety of different species of filamentous algae which is collectivly known as Blanket weed. It grows in dense green masses and quickly becomes an unsightly nuisance if steps are not taken to control its growth. Blanket weed is particularly detrimental to sturgeon as they can get caught up in even moderate levels of blanket weed.
Green Water is a form of algae (single cell) and can look anything from a slight green tint to water all the way to the color (and consistancy) of pea soup. green water, unlike blanketweed, can be treated with a UV Clarifier. In cases where A UV clarifier is either not feasible or not adequatly sized for a particular pond anti green water treatment may be needed.