Aquarium Tips, Aquarium Filtration

Choosing a Custom Aquarium Filter: Canister Filters

There are three commonly used custom aquarium filters to select from when choosing your setup:

  • Hang-on-Back (HOB) filters are the low-end filter,
  • Canister filters are the mid-range filter, and
  • Wet/Dry filters are the high-end filters.

Each has pros and cons, however, when used properly, can keep the fish in your aquarium setup happy and healthy for a lifetime, and reduce the work for aquarium maintenance.  In this post, we are going to explain Canister filters.

Canister filters are the next step up in the world of aquarium filtration. These filters are a bit more expensive than the HOB filters but have much more capacity and flexibility. Canister filters are canisters that sit below the aquarium and have an intake hose and an exhaust hose which carry the water to and from the aquarium. These hoses present a major advantage over HOB filters because they allow you to spread the intake and exhaust ports across the aquarium from each other, providing the maximum amount of water circulation possible. The filters are also compartmentalized to separate each of the three filter components.

Most canister filters are designed to accept all types of filter media, making them totally customizable. In other words, the user has the freedom to put any media into the filter. This can be helpful when battling different water quality issues such as phosphate or nitrate buildup. Canister filters are generally very user friendly and media changes/filter cleanings are rather simple to perform.

The downside to canisters is they are designed as sealed systems. In a sealed system, the media itself cannot aid in the aeration process because the media is completely submerged and no air can get to it. The filter exhaust must be placed above the water surface in order to aerate the aquarium. This makes canister filters a poor choice for marine aquariums unless they are grossly oversized for the application. Having the exhaust above the water surface in a marine aquarium will create a tiny bit of splashing, and this splashing will result in “salt-creep”. Salt-creep is when salt crystals build on areas where salt-water has splashed and then evaporated. This is messy and can be very damaging as salt is extremely destructive to things like wood and metal (typical materials used in aquarium furniture). Marine aquariums also require a tremendous amount of aeration so a wet/dry filter is more appropriate for marine applications.

Have questions? Contact the aquariums experts at Diamond Aquatics and we will be happy to help.