Put my 50 dollars of Canadian where my mouth was and purchased another Emperor 400 to go beside the other one on my 55 gallon cichlid. I thought the water flow would be too high but this hasn't yet been a problem. The mini-rockery probably doesn't hurt either. The new Emperor, however, is significantly louder than the old one. Hopefully it will quiet down, but there must be a huge production variances between them. Jeff