Overwhelmed by the sheer volume of filter products available to you and not sure what is best? Don’t worry. You don’t always need the best. Furthermore, how do you define what’s “best”? If you’re a novice, it’s only normal to seek information about what products to avoid. However, the list of products to avoid in the aquarium hobby is much shorter than the list of products that work well.
Probably one of the best examples of this is filter media. The list of media available for power filters (e.g., canister, sump, HOB) is extensive. In fact, most filter types accommodate all three types of media (biological, mechanical, and chemical). The number of different combinations available is directly proportional to the number of different media types. For example, the number and availability of different bio-media materials alone are high. There are ceramic, composite, plastic, sintered glass, and lava rock just to name a few. All of these even come in different sizes, shapes, surface areas, densities, etc.
So how do you know which to use? Try a few and see how they do with your filter and your water. There is no rule that says you can’t use more than one material. Some aquarists use multiple bio-media types concurrently in the same filter. I do.
On the other hand, some aquarists don’t use any of the material I listed above because they don’t even use power filters. These fish keepers use either sponge filters as bio-media (a type of filtration that utilizes pump driven air to pull water through sponge material), or use wet/dry or sump-based filtration, all of which work very well. Sponges also work as bio-media in power filters, though most people use them there for only mechanical filtration in combination with other bio-media options like plastic bio balls and ceramic beads.
The bottom line is…use what works for you (budget, maintenance time, etc.). As long as you have sufficient filtration to colonize enough bacteria to keep ammonia and nitrite at zero, it doesn’t really matter. I’ve used all of the types listed above and I’ve done so for a long time. Yes, I have some favorite combinations and some that work better than others. There are certain circumstances that will dictate your media choices (e.g., filtering heavily planted tanks, unusually messy livestock, larger than normal bioloads). However, the majority of aquarium set-ups will function just fine with whatever you choose. Experience will tell you what works best for your situation. You’ll learn what leaves your water the most sparkling clean and parametrically stable.