I've got an Emperor 400 that's been running for 5 months and it is very quiet. I just bought a Penguin 125 and started it yesterday and it is very noisy. Colesea is 100% correct that an aged biowheel is quieter.
That said, I've heard great things about the Emperor/Penguin biowheel filters and about the AC's and suspect they are both pretty comparable in their filtration efficiency. People have their preferences and usually have good reason for them. I just found it interesting that I've heard at different lfs's that the bio-wheel filters are vastly superior when it comes to biological filtration.
That said, I've heard great things about the Emperor/Penguin biowheel filters and about the AC's and suspect they are both pretty comparable in their filtration efficiency. People have their preferences and usually have good reason for them. I just found it interesting that I've heard at different lfs's that the bio-wheel filters are vastly superior when it comes to biological filtration.