"Ray @ First Rays Orchids" wrote in message
...
The problem is that the DE sold for filtration purposes has usually been
thoroughly cleaned before packaging, and the washing rounds off the sharps
edges and points.

So then the question becomes "Where can you get DE that hasn't been so
abused?" I have not yet been able to find someone in any local garden
centre who even knows what it is, let alone a vendor able to provide it.

Cheers,

Ted