looking for black substrate with smooth grains
I have a small shrimp tank that currently has pool filter sand in it. I just want to cap it for the nice black look. I'm looking for a black (or very dark) substrate that:
Is smooth and not jagged (rules out Flourite and the typical black sands at the aquarium stores)
inert, or only very mild buffering
doesn't leech out stuff
don't need all the microbial features, but I guess I can rinse it off anyway
won't break down
size 1-3 mm approx
For example, even my pool sand has these little black elliptical grains of about 1-2mm which would be fine.
I also saw on Amazon some black ceramic beads of ~2mm diameter.