We did have an ant problem ourselves once, sorry forgot to mention it before. It was in another property several years ago. Now I don't like to kill anything but they were taking over the kitchen so measures had to be put in place. We purchased an ant trap, they're small and very effective. The ants go inside, take the bate and then return back to the queen and feed her the poison. The idea is that ants are programmed to behave a certain way but once the queen is dead they lose their purpose and the problem usually resolves. Powder is a waste of time as it doesn't get to the root of the problem, which is for every one you kill the queen replaces it with hundreds more. Kill the queen solve the problem. Like I've said before though they're wonderful insects and I would only kill them if the problem was severe.
