Thanks, always wondered how it worked and I'd love to use sand in my bettas new tank when he eventually gets one. Would it be better if I just completely re-did the biorb, popped in a small internal hang-one filter, placed sand over the plastic filter mould and had some silk plants in there for him? I am desperate to get him a completely new tank, but would it work if it came to it?
Just had an idea. What about a regular 5 gallon braceless glass tank, with a lid? I'd somehow ensure holes for a heater and filter, as well as some form of lighting. How does that sound?