I have had problems with ants over the past two years but I am now pretty much free of them.
I listened to something on GQT that mentioned ants do not like being disturbed. They like land that is nice and quiet.
So in that vein I did all I could to upset them. Turning over the soil regular, removing and food sources near them, blocking up their ant pathways when ever i could.
In the end they gave up and decided to move on. Dont like poisons with having a little two year old and also a silly dog. Same goes with slugs and snails, get out there in the evenings and physically evict them.