Kind of off topic here, but I had our pond treated when it was built. Rex (Rainman) came out with his pontoon boat and sprayed the alum mixture. The transformation was incredible. The water went from clay colored brown to crystal clear in a very short time.
I’m not sure that the clay wouldn’t have settled out anyway, but the water never would have cleared up to that degree.
So now, ten years later, did it make any difference? A few weeks ago we had 20” clarity measured with the Seiichi disk. I realize that’s all algae dependent, but did the alum treatment make any difference? Would I have been better off investing in aeration? I really have no idea. The water was pretty amazing, at least for a few weeks.
However, even today if I wade out off the bank, clouds of clay particles come up around my footsteps, but immediately settle back to the bottom. Is this natural, or the residual effects of the alum?
Just food for thought here. I’m obviously not a scientist.

12 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (decreasing), SMB, and HSB (only two have been seen in 5 yrs)
I think that's about all I should put in my little pond.
Otter attack in 2023.