If you pour in the alum without turning it into a slurry, it will sink to the bottom and get covered with what little debris falls to the bottom. This renders it effectively useless as it will not mix.
I didn't have that problem at all in my pond. I can dump a 50# bag in shallow water, and the white blob of alum will be completely diffused and gone in 3-4 hours.
Bobad, thats true in the shallower areas since there is FAR less suspended clay and it is "mixed" (poorly) with the water from wind/wave action. In water deeper than 5 feet it is virtually useless to add alum that is not in a slurry since it can't mix well enough. Depending on how much is in suspension (Assume a lot otherwise alum isn't really needed) The deeper the water, the thicker the sediment cover and the less alum dissolved. this quote was copied from this website
Langston Universty/Aquaculture---Clearing Muddy ponds "How to apply
Apply alum to the pond in calm weather. Alum must be applied evenly over the surface of the pond and rapidly mixed into the water column. For small ponds, make a slurry of 1 part alum to about 10 parts water and apply to the surface. In larger ponds it is more effective to use a boat with motor and pour the slurry into the prop wash as the boat is guided back and forth across the pond.
Clearing should begin in a few hours and continue for several days."
You need to make the alum slurry so it can "fall" through the water column slowly to be the most effective. Alum will dissolve but does not mix with water_that is why it is called a slurry. If you pour in the alum without turning it into a slurry, it will sink to the bottom and get covered with what little debris falls to the bottom. This renders it effectively useless as it will not mix.
FWIW Alum is best sourced from larger chemical suppliers and averages 32.5 to 37 cents per pound.
