Jim, good idea with the GSP. They will grow on just about anything and would cover it eventually.
Tom, I've seen video of that happening with the tunz wave box, but I think it was caused because the person had it set wrong. I believe the tunz box comes with a controller. The Wave2k doesn't need a controller because it works differently. I have noticed that it does agitate the surface water (like a power head would) and there is a slight up and down movement of the water, but there is not enough to cause any sloshing. If I get a chance I'll try and make a short video of it in action.