Do you mean the 6215?
I have been testing a 6208 in my 4x2x2 for a few weeks, although this has just been part of my fresh water leak test. I was quite happy with the wave created and will be interested to see how things go with corals etc.
My wife wasn't quite so happy as she didn't like the sound of the pump turning on/off. Hopefully she won't notice is as much in salt water and with a couple of other Tunze pumps in the tank.
These waveboxes don't seem overly popular although I am not really sure why :confused: