I am currently running an Aquaclear 50 and Emperor 280 on my 46 gallon bow front. I have 9 African cichlids, all 4 inches or less. My Aquaclear is newish and I am happy with it so far. My Emperor is 10 years old, still runs like a champ. But...it is getting old and lately the motor seems to be a tad louder than before. It's not the impeller, I've heard that noise before on a different filter! I am now considering replacing the Emperor with another Aquaclear. Should I? If so, should I get another AC 50 or bump up to the 70? I have ceramic bio rings in the extra cartridge of the Emperor. If I transfer those to the new filter, will that be enough to prevent a mini cycle?