Dear Benjamin
The white residue you have found on the glass is more than likely a little calcium carbonate precipitate.
This can occur if you mix the salt into a new tank too quickly and the salt builds in mounds and precipitates
locally.
This is totally harmless and will clear once it flocks due to bacterial action once live rock has been added.
More information can be found at the links below:
http://www.theaquariumsolution.com/sight-cloudiness-fresh-mixed-h2ocean-salt
http://www.theaquariumsolution.com/mixing-h2ocean-reef-salt
With regards to scratching the glass any precipitate attracted to the clean glass will be much softer than glass
and very chalky so it wont scratch.
I can only advise you check your algae scraper for foreign objects. It is quite normal for aquarium manufacturers
to clean of small areas of silicone with fine wire wool. If they haven't cleaned the aquarium out before shipping
it's possible tiny pieces of steel wool have stuck to your magnetic cleaner so please check the cleaning surfaces.
Hope this helps
Tony
This was from a rep at H2o I'm going to add live rock