Ants around pond

I'm getting ants in the dirt around my pond.
Mostly in the mound of earth around the waterfall pool
and under the coping stones.
Went to sink a plant today and uncovered a LOT of ants... again.
Problem is what to do about it.
I've been digging them up and pouring boiling water on them,
as I am afraid to use poison around the pond.
The only thing I can think of is possibly Diatomaceous earth.
Anyone else have this problem?
What if anything can be done about it?
They're wearing me out.