Bought this Curve 7 protein skimmer to replace an old Euro Reef that was outdated but still functioning otherwise. I got the model with the default Rock SP2000 motor and find the bubbles produced are fine and many and the operation is silent. This is a quiet skimmer that does the job, has water inlet adjustment that is useful, poor instructions, but a lot of YouTube videos that will help anyone put it together in less than 15 minutes. ReefSupplies staff expertly recommended this size for my total 230 G system and it takes up much less space in the sump than my old EuroReef from early 2008. The pump sits inside the foam fractionation chamber and that reduces its footprint a lot. Its a Chinese company that has come a long way since they started in 2005-06, and the price for the skimmer is economical. Working Depth is closer to 18-20 cm, not the 25-27 cms as printed in the instruction sheet. I used a support below it to raise it in the sump.