Ok, here it is...

http://www.maast.org/forums/showthread.php?t=50019

I had thought about creating a tide pool/jetty styled tank by alternating the water from the left to the right in sequence with the natural tide with some cup and bowl sized divets in some rocks to simulate a real tide like environment. One side low, one side high at all times... or maybe both suffering the effects of the tide while one side had a turbulent wave action while the other side calm and peaceful during the high tide.

But then I got my niece hooked and she claimed the tank. I would have to run this by her if you become truly interested.