Tbh it would take months if not years of nutrient build up on the glass to actually etch it. I work for a float glass company....and have also dealt with this etching issue personally....i would think this would be more of a coating and adhered issue then an etched one....great video but even with alkali etching not all hope is lost....cerium oxide does do the trick if using a certain technique obviously tank cant be full or in use but can polish the iron off the glass to get the alkali etching off.
When you say you administered in four parts. Did you add 1/4 of that gallon of mixed solution at a time to your aquarium?
