Well that annoying I was going to pick up 2x 6025's with the Nanostream Rocks.
How was it positioned in the tank?
Not sure if the 6025 will have the same problem unless you run it pointing down.
If you look at the 6020/6040, the wire comes out of the bottom of the powerhead, so it has to do a 180 degree turn unless you want it on its side or upside down:
Tunze's own pictures have it up that way, so it's not like they could say I was using it wrong!