Just as a follow up:

I bucked up for that Amdro stuff even though it was 4 times as expensive as everything else on the shelf (still not bad at $12).

It came in a 24 ounce container and the directions said I only needed 2 ounces to eliminate a whole colony, so I was kinda skeptical, but I followed directions.

Immediately after sprinkling the stuff I saw ants picking it up and dragging it down their holes. There's a real insidious side to me that really loved watching that scene go down.

Day 2: I go back to the nest and notice a lot of the pellets still there, so I'm thinking they didn't take much of the bait. Then I disturbed the nest, something that would ordinarily result in 100 black ants pouring out. Nothing. Not a single ant showed up to defend the nest.

Flash forward to Day 7: the nest appears to be completely abandoned. I'm also finding dead ants along the floor boards of the house. I'm guessing these are ants that deserted the nest and are on their own, dying in the process because they need that whole nest structure to eat and live.

Gotta give this Amdro stuff my 5 Star Lead Pipe Lock Two Thumbs Up personal guarantee.