(~Roy~) wrote:

I have to think when the properties of alum is tied up when it locks
up the phosphates it merely winds up basically like an inert
ingredient on the bottom of the pond. Now if there was no phosphates
to lock up I could see a high level of it occuring, and then possibly
be a problem........sort of like giving medications when nothing is
actually required....

It is not so much the phosphates tying it up, but the pH. The aluminum
becomes a problem at low pH's. In ponds, the pH is usually managed.

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