Best way to remove sani-tred paint from basement walls
I would try a Muriatic acid and water solution. I know the Acid will etch the Block just not sure how well it will remove the sani-tred.
I would start with a 10% acid solution and work up from there. Usually I do this to floors prior to painting.  If I need to make the surface rough for better bond for tile it works also.
I have used mixtures up to 30% depending on how aggressive I want to etch the cement. You will need fresh air in a basement as the fumes can get quite strong. Remember to always add acid to water and use rubber gloves to protect your hands. All pool supply stores will carry Muriatic acid and most home improvement carry it. It is not that expensive for a gallon to give it a try.