Who, What Where? Oh yea, Kitty litter

OK, so after going all over hells half acre I finally found a place
that sold just plain clay kitty litter. No fragrences, no addatives,
no crystals, just plan ground clay. Ironicly, I found it at Farmer
Jack.
Anyway, now the question is how much and how do I apply it to the
pond? Put it in the skimmer basin, sprinkel it around the pond, put it
directly on the string alge. (On the last one I'll be doing this all
night.)
FYI... my pond is about 2500gal. with alot of string alge in it.