Water Gardening: I have a small acid bog that I am having edge promblems with, 1 by Equilibrium

Equilibrium wrote:
I created this small acid bog using a kiddie pool. I purchased cultured "L" shaped stone to edge it. The edge does look nice but deer are actually walking right through it and knocking over the edges that are sort of balanced precariously until I fill in around the perimeter. I have heard of this product called Great Stff. What is it? Where do you get it? How do you use it? And would it work in this situation to secure my edge?

Here's a photo of the edge-