It releases lignins when it decomposes. These lignins then oxide to humic
acids which then get converted to hydrogen peroxide when sunlight shines on
it. Hydrogen peroxide does not stop existing algae, it only limits new
growth.

Oxygen is required for this to work and if you have little O2 in your water
your fish will suffer oxygen starvation. It takes about a month for the
whole process to kick in.

Sam


"tasha" wrote in message
...
Hi there
I heard that if you weigh down some barley straw in the bottom of your
pond,
it attracts all the nutrientys and algae and helps to keep it clean and
clear. Is this true?