Fishhead, you ask a lot of questions I don't know the answer to. Here's what I know. My pond is about 10' deep right now. It's only about a third of an acre and in the back yard. We also have frontage on a comunity lake about 15 acres and up to 25 foot deep. The community lake doesn't have a problem with FA. They have a problem with BG aleae from time to time. We have all of our ponds aeriated. Comments are based upon my property and my pond. I'm a work in progress as my pond clarity increased from 1' to about 6'. This past year I've noticed some watermeal. But 90% of the pond surface area is clear. If FA gets to floating too bad, I get the garden rake out and do some collection.

I don't know what depth the bacteria is able to work. It is aerobic bacteria so it must have an oxygen supply. It should not be applied unless the pond temp is at least 60 degrees, otherwise it won't grow. But I've noticed some significant increase in scum recuction and pond clarity.

My observations... Hope this helps.