Okay - I'm confused.

I *do* want to use calcium carbonate based sand because -
It will help keep up the calcium & alkalinity & pH & trace elements as the
sand slowly dissolves into the water. AND it won't scratch the glass like
a silica sand.

I *don't* want to use calcium carbonate based sand because -
Calcium will preciptate out onto the CaCO3 sand and cause the
alkalinity and pH to drop. I will have a heck of a time maintaing calcium
& pH. Better to use a neutral silica or perhaps aragonite sand.

What to believe?
Thomas Bartkus