Just for the record I wasn't referring to using the alum to clear the water, although that may be a byproduct. I was proposing it to tie up the nutrients in the bottom of the pond, hopefully speeding up the reduction of your excess nutrient problem.

It's a sound principal and it was used on a state owned lake in my state with good success.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.