That looks great, I have always wondered what a fluid bed sluice with a pump would look like. Do you run any matting underneath?, and also how do you get the water into the box underneath?. I know you probably have a secret way but that is cool, I just think it is fantastic.
For those with questions I posted how to make it, with measurements and others on the forum posted quite a few pictures in another post. just do a search on Fluid Bed and they should turn up.