white deposit on rocks in waterfall pond

We have tried Professionals and all kinds of products to clean off the white deposits on the rocks. Nothing works. We even tried acids and wire brushing the white off of the rocks. It looked a little better but the white remained. I dont know if it is hard water deposits or what. Can you come up with several possible solutions that I can try.

 

Dear Peggy:

Sure, no problem. I whish that all queries were this easy!

How about if you leave that poor stone alone and learn how to like it the way it is?

I mean, what on earth did it do to you to be treated it like that?!

Whatever that stone is, it is obviously not the right one for that application, if its getting whitish bothers you so much. Well, it's not its fault, is it?… J

Ciao and good luck,

Maurizio Bertoli