I have to agree with the previous answer, the Nippon Bait stations are brilliant but it took about a week to ten days to clear them all for us. In our case, the ants have been walking though the house from font to back under the floorboards and coming up under the sink, so we also bought the Nippon powder and covered the cracks and crevices on the drive with it, and bought the Nippon Spray and sprayed the floorboards under the sink unit and anywhere else we thought they might be coming through, of course avoining any food preparation or storage areas. However, I have been warned they are notoriously difficult to get rid of, so I am preapre for the same to happen next summer.