Most of the ponds with successful spawning of SMB in my area have limestone rocks of various sizes as substrate. Limestone in NW Ohio can be obtained in at least two grades of hardness, a ligher colored softer type, and darker colored (blue-gray) that is considered hard with very low soluability close to natural igneous rock. There should be no problem as far as the SMB spawning success if you use quarried limestone.
The small amount of limestone that you are proposing to use will not cause adverse hardness in your water. Many ponds in my area use it to completely line the top shoreline down to 3 ft deep. Total hardness in those ponds that are built in limestone based clay soils run around 180-230mg/L total hardness. Total hardness of neighboring ponds that have natural washed gravel (igneous rock) for the top perimeter lining also have similar total hardness values of 160-230mg/L.
Last edited by Bill Cody; 10/17/08 03:13 PM.
