I'm pretty excited by a new addition I made to my tank a couple weeks ago...a waterfall!!! I took bought a deep granite dish that I pushed into the sand so the top is just a bit above the surface of the sand. I boiled a cup or two of larger "gravel" stones (natural) to add the dish (to prevent my smaller crabs from drowning and make sure they all could easily get out). I used plastic "fake" rocks called "Lok Rocks" to build the rock structure for the water to flow over. To create the actual waterfall part...I took apart a small Duetto submersible filter (removed the bottom half that had the filter parts) and placed it behind the rock structure. I had to turn the flow guage down a bit to prevent so much splattering of water outside of the dish, but now it's flowing great! It took me a while to rig it up so that it works well, but now that I've gotten it I'm pretty excited!! Aside from looking pretty and sounding soothing, it seems to help keep the humidity up as well. It also provides my crabs with a nice deep dish of fresh water if they want to submerse. Again, I'm sure it's something that I like more than the crabs do, but oh well!!!