Ag lime is ground limestone and is spread over the pond bottom or in pond and surrounding land to slowly adjust the water chemistry giving it more hardness and alkalinity in the form of calcium carbonate. This will buffer the ph swings during the day caused by plankton and vegetation.

Gypsum is added to clar up muddy water by causing the particles to combine into larger particles which will sink. It doesnt effect the pond chemistry much. I prefer Alum, or aluminum sulphate which can be used in much less amounts. It will cause the water to become more acid, so quick lime or calcium hydroxide is used in conjunction with alum to neutralize the acidity.

Last edited by burgermeister; 04/15/09 10:04 PM.