Tested the Ph and is was slightly acidic, but only due to the used water being rainwater.
Originally Posted by Firerock
Seems like the glass is clean
Glass is no more or less than silica sand that has been melted and re-solidified into one smooth piece (basically). Silica sand is the kind you want to use with CP's anyway, so I don't see any reason crushed glass wouldn't work well. Silica is chemically inert and shouldn't alter the soil chemistry at all.
So far all of my sundews and venus flytraps are loving it. I'm trying it for my pinguicula and a few other species as well.
Conclusion: glass works