Yes, the silica stone diffusers shoot bubbles out all sides, but they're attached to a manifold, and often the manifold sits on a pvc plate (like this:
http://ecx.images-amazon.com/images/I/71kopRSUHrL._SX522_.jpg). So, unless the plate settles onto the lake bed upside down, it won't be shooting bubbles down.
We shut down our system for the winter this past week. When we start up again in the spring, I'll take photos right before and after and a few days after too. I want to get some objective observations.
I am super-interested in hearing anyone else's experiences.
