This stuff works good and is available at Tesco:

About 55 baht.

buy pkt crackers

place in ac unit and light

remove all ants and bonus remove all dust

The Borax from healthfoodthailand just arrived.. doing experiment now.. first i put it on the sink but the water seemed to roll down the washbasin leaving sugar exposed, i think alot of them were just eating the sugar, now I got rid of that after shooing them away and i put the solution on a cutting board and they have moved their feeding operation to the cutting board.. will see how well it works.

Mix it well, until the sugar and borax dissolve.