A newbie - with white marks and usual noise

Hello all, got myself one of these very stylish aquariums last week. Set it up, left it running for three days as shop said, then as they advised I put my fish in. Two deaths so far.....but I was expecting some problem - most likely my fault for putting them in too soon.
Anyway, couple of things - the filter is very noisy, but I expect having read other threads that it will calm down over a few weeks.
But more oddly, there is what looks like a water mark about two thirds of the way up - the tank was definitely new and unopened - any ideas? Bit of a shame really!!!!
Thanks
Greg