I have a 75 gal aquarium I have a bearded dragon in...i used to have a ball poynton in it and the people that had it before me had fish in it...there is a white residue built up on the inside of the glass that I can't get off...i have scrubbed it and scrubbed it but can't get it off...does anyone know how to get this stuff off...i was told it is a lime build up from the water