Any degreaser will get rid of soap and then a good rinse !

mark Bannister wrote:
She thought she was doing a good thing, and fortunately there are no
fish yet. The pond was supposed to be up and running last year, but I
just now got the tile finished. It's a small formal pond, about 700
gallons, tiled with granite. My daughter used half a bottle of
dishwashing soap to clean it. Now it's a great big bubble bath.
I've rinsed and rinsed and still have a bubble bath. Will sunlight
eventually break down the soap?

Mark B.