South Down in Calgary???

[Bob I]

I would say that is probably true, but to what extent? I find that Aragonite scratches also. You also have to weigh in the extreme cost of Aragonite, and its relative few benefits if you are using our local water. Right now I have a mixture of sugar sized aragonite and silica sand in my nano. If you keep the sand on the bottom where it belongs, scratches can be minimised. Small tanks are inexpensive, so if you were to inadvertantly scratch one, you can cheaply replace it. :D