Grime Line on 75g tank
 

I recently got a used 75g tank. When I got it I cleaned up the tank and got it set up. However now that water is in it I noticed that the top inch of the tank has a white tint to it. It looks like it is a faint line or mineral deposit. I have tried scraping it with a razor blade scraper but with no luck. I would really like to get rid of this line but I don't want to drain the tank, I just got it going less than a week ago. Any tips for getting this stuff off?

Sounds like lime deposits, have you tried vigorous elbow grease? it should really come free with a soft cloth and hard work.

Scrubbing
 

I scrubbed pretty hard but Ill really give it a go. I tried a razor blade but it couldnt really get under the light stuff. The heavy deposits came right off with the razor.

Ok, I could be wrong here - but I'm sure I heard someone mention vinegar once. Just rub it along the glass where the mark is - being very careful not to get any in the water.

Vinegar
 

I heard that too somehwhere going through posts. Next time I do a major water change Ill give it a shot. Ill try soaking a rag with a little vinegar then dabbing the lime.

Ok, good luck with it - let us know how it goes :)