That website is about managing muddy water (suspended clay) and has
nothing to do with the algae which is blanket algae or string algae.
This algae is living on nutrients in the water and uses sunlight to
grow. Shade and removing nutrients with filter plants will help prevent
it. You can also use barley straw:

http://www.sfr.cas.psu.edu/water/str...ct%20sheet.htm

I get my barley straw from our local Ace Hardware store (Weavers).

Sheetrock is gypsum. Read below...
http://www.conservation.state.mo.us/manag/clearpon/

Hi - my neighbor has a 1 acre stock pond that get's covered in Algae all
summer long. I've heard that throwing cut up Sheetrock help dissapate it.
He's all for it but neither of us know what damage we might do. There are
currently no fish in it but a lot of frogs and turtles.

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