question about sludge eaters

Do these products eat away at algae trapped in a gravel bog filter. If so,
what is the best brand? We just built a new one, and there's lots of algae
on the gravel as it starts to clear up the pond. Don't know what effect the
taro and iris will have. That's all I had on hand to put in there, so far.
It's still warm enough to grow some things here. It probably will be for
another month or so.