Yep, really. Been using it for years. Note that I always clean the glass first with glass cleaner and use the steel wool for stubborn places or streaks. Maybe you got some hardened steel or used some type of steel wool pad with an abrasive added. Or more likely, could some hard mineral in the aquarium (sand?) have gotten picked up and scratched the glass. I certainly would not try steel wool on windshield glass that possibly had dirt and grit from the road - that could contain particles of some very hard minerals. I once put a scratch on the inside of a windshield by swiping at some fog with the back of my gloved hand. That glove must have had a single particle of grit in the fabric. Diamond polish to the rescue.
From this page:
https://expandusceramics.com/qa/what...tch-glass.html:
Does steel wool scratch glass?
Please be advised: while steel wool and brass wool will not scratch glass, other cleaning abrasives, such as S.O.S. pads, will absolutely scratch it and must never be used to clean it.
Some wise advice:
https://info.glass.com/steel-wool-clean-auto-glass/
JKJ