Qetjustin,

Before you add lime with the Alum to your already hard and alkaline pond water ... Read this article.. The protocol for discovering the goldilocks treatment is there. The suspension should break at a safe treatment of Alum (also tells you how to determine this). If the suspension will not break within this limit, then lime would be needed to increase the treatment.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers