This arch top sealed unit would have lost it's seal quite some time ago. Allowing outside air and moisture in between the two layers of glass. Eventually evaporating and leaving behind the pollution and impurities which will eventually etch into the glass surface if left long enough.
We took the measurements for the new sealed unit, approximately 1 week before installation. Taking templates as necessary, like with this arch top sealed unit. This sealed unit was installed into its vinyl frame in about and hour. Leaving a beautiful view!