White haze on inside glass

[ZoWhat]

White haze on inside glass that's very very difficult to scrape off...even with a razorblade. Comes off if the razor is at the correct angle.

What is it?
Seems like some kind of hard calcium

Best way to remove?
Other than the painstaking method of using a razorblabe


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[vaguelyreeflike]

Seems like calcium precipitation. What is your magnesium, calcium, alkalinity and PH levels?