A couple years ago I remember posts about black sand containing a ferric (iron) component and therefore your mag-cleaner picked it up and potentially scratched your glass.
I don’t know if it was one brand or all brands of black sand, and whether it is still true today, but it is one thing I’d be checking out.
hey paul - that was me...its in my tale of the tank from 4 years ago...LOL.A couple years ago I remember posts about black sand containing a ferric (iron) component and therefore your mag-cleaner picked it up and potentially scratched your glass.
I don’t know if it was one brand or all brands of black sand, and whether it is still true today, but it is one thing I’d be checking out.