If you go with a reg bio load community fish, go with an aqua clear 110 HOB. Save your money, I was running a Rena xp2 with the ac110, then Rena xp2 with a stock whisper HOB, then back to AC110 alone. My params have stayed consistent and it's cheaper than the alternatives. If you go with a cichlid tank consider a eheim or maybe a marineland. ( I am aware they were bought but they are different). I also ran a submersible fluval ?something or other along with Rena and didn't put a dent in numbers. For "rule of thumbs" stocked 55, you don't need a canister, you just need reg maintenance and a good ol HOB. I am a advocate of AC BC they are quiet but I have heard complaints about noisy motors but not sure about what years these were produced.