what's the difference between power filters and bios and any other different ones?

I know that the penguin filters are good or you could get a bio wheel.....I am not to sure what the differece is between them, But I think personally that the penguin filters are good at least from my expreince, they are a little pricey but worth it I think.....someone elese with more knowladge than I should be along shortly.......

The Penguin, Emperor, and Bio-wheel filters are all Marineland products.

The Emperors are supposed to be better than the Penguins, but the Penguins do just fine. Those two filters have a three-part filtration system: fuzzy stuff to take the extra food and chunks of poo out of the water, charcoal to take medicine and chemical stuff out, and a bio-wheel that grows bacteria that help keep your ammonia and nitrites down.

The Bio-wheel filters, as I understand it, just have the bio-wheel part. They're for adding on to other filters that don't have a bio-wheel; they won't filter your tank very well on their own.

I would go with a Penguin filter. The consensus on them seems to be that they're pretty darn good.

It depends on what size tank you have as well, the bigger the tank the more likely your going to want to get a canister.