Many of the small ants aren't looking for sugar, they want fats. Try mixing boric acid into some melted chicken fat, then let it solidify.
Too much boric acid is gritty to the ants, and they'll avoid it.
I filled a small container lid with that mixture, and the ants were ten deep trying to get to it. They worked for 3 days and left it totally clean. They didn't come back.
--Gene