Barley straw question

We are still fighting the green pond thing although the water is clearing a
bit, thanks in part to something from Laguna that is supposed to make the
suspended alagae clump therefore making it easier for your filter to grab.
Not a big fan of the chemical thing, but since it said nothing about killing
the algae I figured I would let the SO have his way and try it. The LFS has
bags of Barley straw pellets on sale that I would like to try but the SO
says that the tannins in it will turn the pond brown? I had never heard
this but this whole pond thing is new to me.
Thanks for the help
Elaine