Are these salt lines on the glass? Or something else?

[saltyfish24]

I regret not cleaning this used aquarium better. It's a Biocube, and I used vinegar and paper towel method to plaster the inside, and then rub it down with vinegar. It seem clean at the time, but after filling with water, it definitely is not. I'm not sure if it's even salt line?

Now that I got sand and water in it, what's the best way to approach it? drain it and clean again?

 

[Tahoe61]

Image under white lighting please. Typically I take a razor blade to the water line during water changes.

 

[saltyfish24]

Image under white lighting please. Typically I take a razor blade to the water line during water changes.

Oh weird, I thought I posted an image with my original post. Here it is:
I didn't think of using a razor.