I plan on doing this to my 75 gallon goldfish tank, as soon as I get settled in my new apartment.
I LOVE underwater waterfalls, and it's always been my dream to have one. But one thing that I plan on changing is that I don't want a waterfall on both sides...no, there will be a waterfall on one side of mine and the other side will have my volcano bubbler.
I plan on building rocks up around it and using red sand on that side to simulate magma flow.
I just can't wait to get started! I know it'll take some time, but it'll be worth it in the end, I'm sure.