There's much on the forum about an O2 crash when treating too big of an area.
Treating too much
biomass of algae (
or submerged plants) at one time, with any product, is of greater concern than the size or percentage of
area that is treated, since it is the decomposing plant or algae biomass (actually, the oxygen-consuming microbes which break down the dead biomass) that increases the pond's biological oxygen demand (BOD) and potentially leads to inadequate oxygen-levels for the survival of fish.
Just wanted to clarify that second sentence, since treating a large biomass of submerged plants or algae - even if they occupy only a relatively small portion of a pond - may lead to DO issues under certain conditions, especially as water-temperatures increase.
