Wait till you see the make of the Tunze 9002. cheap flimsy plastic casing.
But hey, it does its job well.
Yes it is rather water level sensitive. I do not have a ATO but manually top up the water in my 1.5 ft cube 2x a day.
The Performance is good though it does leak some micro bubbles into my tank.
If I ever change my skimmer, it will be just for the MCE 600.