Calcium in a freshwater tank?

[drag13honda]

I was wondering if there is such thing as "too much" calcium in a freshwater tank and if it has any adverse affects in fw tanks? Is there a safe/preferred level?

I know inverts need some sort of calcium for optimal health. I have been looking at a substrate that is for fresh/salt water that has added calcium. Just wondering if there would be problems with using this in a fw tank.

[Michael]

Most tapwater in the DFW area has plenty of calcium already, so there isn't any need to add more in the substrate unless you are keeping a species with an unusually high requirement.