Here's my two cents on bacteria and my observations. First off anaerobic bacteria obviously cannot keep up with the amount of debris entering some ponds, that why there is a build up in the first place. I do believe aerobic bacteria can digest much faster and reduce sediment. Think of a wood post in the ground such as a fence post which has been there for years. When the post breaks off where does it break? Always right at the ground level. Why, because the exposed post is dry most of the time, and the bottom has moisture most of the time. But if it were just water breaking it down then the bottom of the post would decay first as it is in the wettest environment. If you dig out the post bottom you will find it is in good shape yet. What has happened is right at ground level you have both moisture and oxygen and the post rots fastest there. Also note that nobody added beneficial bacteria to the post, it was already there. It may be possible that some ponds do not have the beneficial bacteria so adding it once may help. I view that as in the "it can't hurt" category. I view my pond like the fence post where the moisture starts (ponds surface) there is oxygen as you go deeper you may not have as much or any at all.
