It would take a LOT of broken concrete to significantly change the amount of calcium and total hardness ina body of water. Many water bodies are often too low on alkalinity and hardness.
I would keep rock piles out of areas or flats that you might want to seine to sample your fish. Seining is a good management tool.

Last edited by Bill Cody; 05/09/12 07:59 PM.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management