milky film

[Plonk]

I have finally started to get my tank ready and set up and today I am cleaning the tank out with warm salty water. I have a problem though, the tank is secondhand and there seems to be a milky film all around the top sides of the tank. I have tried to wipe over the tank and also scrub the area gently with a soft scoura but it doesnt seem to do anyhting. I have no clue of what it could be.

 

[Jennewt]

It could be hard water deposits. Vinegar will help remove this. If not, a razor blade will do a better job.

Some areas have silica in the water supply. When silica is deposited on glass, there is NOTHING that will remove it, as it bonds permanently.

 

[Plonk]

Can this be harmful if I leave it there?

 

[MRIGUY]

It should not hurt anything but it is unsightly. As Jenn said you can use vinegar or some people use lemon juice. Try both and see what works. Make them into a paste with baking soda and scour with an unused sponge or paper towel. Rinse well and you should be good to go.