MsH, KapHn8d....I have never gotten good results with less than a 200 pound dose of alum slurry, followed by 100 pounds of Hydrated lime per acre foot of water volume.

As for an "overdose" of Alum, that is an extreme amount...probably in the range of 5000 pounds per acre foot.

If there is any "trick" to applying the hydrated lime and alum, it is to apply the alum, as a slurry, proportionately to water depth followed by Hydrated lime, proportionately, but also in "strips" so the Hydrated lime can spread slowly and avoid any risk of pH shock....Alum does not dissolve into the water, Hydrated lime does...Alum lowers pH relatively slowly while Hydrated lime raises pH to lethal levels very quickly.

MsH...Alum applications are not cumulative...If you need 200# to clear the pond, but instead apply 4 app of 50# each, you will still need 200# applied to gain clearing.