We also have had problems with ants, mostly the little black devils. My son dumped moth balls on the nest, not to get rid of the ants, but to get my wife's cats to stop using the area as a toilet. Pooping in an ant hill just goes to show you how dumb they are. Anyway, the ants moved the exit to their nest about six feet away. If we do this a couple of more times, they will be in the neighbor's yard.
I have been told that if you whip up orange peels and water in a blender and then dump that on the ant hill it will cause them to move their exit hole. I haven't tried it yet.
I draw a circle around the feed barrels with Chinese chalk. It is sold in Asian stores. It says very plainly in English on the box "Read and follow the enclosed instructions." which by the way are only written in Chinese.
When I first bought this stuff, the kids said "that has to be bogus." But I drew a circle around the cats' dish before I fed them. Within minutes, just like clockwork, the ants appeared. They walked across the chalk line and promptly died.
After that, I was a believer. But I also made real certain that I never touched the stuff with my hands. I always put a plastic bag over my hand first. Then the bag goes into the trash when I am done with it.
I remember when I was a kid, one summer we had such a plague of black ants. We had to put the bed legs in cans of water. Finally, my father noticed that the black ants would not crawl on black rubber. He cut up old tires and inner tubes to put under things. It worked. Why they don't crawl on black rubber, I don't know.
I think the only real way to get rid of ants is to move.
Good luck,
Rufus