I'm in the process of setting up my first salt water tank. It's a 135g previously used as a freshwater planted tank. The water was very hard, so there are a lot of hard water stains on the glass brace that goes across the top of the tank. I think these stains have a significant impact on the amount of light getting through. Any good ideas on how to clean the hard water stains from the glass? I've tried vinegar and it didn't work all that well. Thanks.