An alkaline concentrated detergent composition for use in cleaning hard surfaces, medical instruments and other metal components (parts, tools, utensils, vessels, equipment) having superior cleaning efficacy at much lower alkali content than traditional alkaline cleaners and enhanced scale control properties even when diluted to about 1/40 ounce per gallon to about 1/10 ounce per gallon in potable water and even in exceptionally hard water. The inventive composition maintains its superior cleaning efficacy and scale control properties during use.