See below, I think I have calcium beginning to build up on my glass tile. How do I remove it? If it's something other than calcium, what is it and how do I remove? Thanks in advance!
That looks like efflorescence.
I had the same on my waterfall after a year or so. I used a diluted solution of muriatic acid and a bristle brush and it melted right off.
See this thread for more info, will need to register to see the photo.