I recommend a mixture of boric acid, sugar and water. Make a paste. Place it on a small tray or plate near where the ants are seen. They will take it back to the nest and the entire nest will not be a bother. It is also pretty harmless to humans so safe to use around the house.
Absolutely works. We had a real problem with small black 'sweet' ants and we tried store bought baits that were supposed to eliminate the source and they did work but only very briefly. Then my wife told me about the borax mixture and we made a batch. I went outside and tracked where they were coming in several places and set the bait down over several days. Then went out with a can of Raid ant spray and got rid of the stragglers. This was over two months ago and zero problem. Some are still in the walls but the main sources outside the home where they we coming in like a swarm are completely gone. My understanding is that you really need to identify what type of ant you are dealing with. Trap some on some tape and take it to an exterminator and they should be able to tell you. This borax remedy, for example, doesn't affect the small red ants I see from time to time in my yard or other types of black ants. It is my understanding that there are many different species of ants each with their own behaviors. Good luck.
Yes, I do this too, every spring when the ants come in the house. I also add cornmeal because it bloats their bellies and kills them quickly.
And it is not poisonous to pets, kids or adults. And it doesn't add harmful chemicals to our water table.