I have a shallow starfire glass aquarium and today I did my daily maintance and realized that dome dull spots on my glass were permanent..I thought they were Calicium but it is surely in the glass..no razor blade helps..i just removed a heater from this area and wonder if this is the reason..i want to prevent any more areas..i have never seen anytinh like this..it looks like a haze..glass is dull like when you breathe against it..please any input..may be this post helps sb else too to make the same mistake..what am I doing wrong???