Keepers of medium to large sized aquariums everywhere have long debated the merits of their favorite filtration methods. In the past, it was the undergravel filter that was so beloved, but today, hang on back filters, often known as waterfall filters or HOBs, and canisters are the most popular pieces of filtration technology. Both have their uses and die-hard fans, but neither piece of equipment is perfect for everyone. Let’s explore the advantages of both filter types.
Hang On Back Filters Get the Job Done
Many beginning aquarium hobbyists rely heavily on waterfall filters, especially those keeping smaller tanks. In aquariums under 50 gallons, they’re almost the default choice for initiate fishkeepers, but popularity doesn’t necessarily equate to effectiveness. If you’re considering a HOB filter for your next tank, here are a few reasons it might be the perfect choice for you:
. Unlike a canister that can cost several hundred dollars, even high-end HOBs are typically under $100, no matter the size. Their relative value is just one reason that they’re so popular, since they often allow aquarium keepers to get into bigger tanks for much less.
They’re easy to setup
. Even die-hard canister filter lovers won’t argue that HOBs are significantly easier to setup. Out of the box, you can have an HOB running in under five minutes, and that’s if you stop to read the directions.
They don’t need much maintenance
. HOBs are designed to be super simple machines. You put the filter pad in and turn it on, the filter sucks water up the intake tube, then lets it trickle through the filter pad and back into the tank. Because of this simplicity, there’s not much to go wrong and only the single filter pad to change.
Although you may have to change that filter as much as once a week, it only takes a few minutes. If the intake tube gets dirty, it’ll pop off and can be sprayed out with a kitchen sprayer. Every part of a HOB is designed for easy care, which is probably why they’re popular options for casual fish-keepers.
Air and water mix in the chamber instead of relying on dissolved oxygen
. This might not seem like much of a bonus, but your fish would disagree. Canister filters rely on there being enough existing dissolved oxygen in the system, but a HOB can actually bring more air into the water to help keep your fish healthier without added air stones. If you’re forcing CO2 for plants, this feature will backfire, though, so keep that in mind if you’re planning a planted tank.
Canisters Get the Job Done in Style
HOBs can do a completely acceptable job of water filtration and work great for people who don’t want to tinker with their water levels too much or have any inclination toward touchy or difficult to keep fish. However, if you need precision control over your tank conditions, a canister is the only way to go. Here are just a few reasons that canister owners choose them:
They provide for more flexible water treatment
. Like a tiny water treatment plant, canisters can be customized to create any sort of conditions you might need. With several baskets inside the filter, you can design a program all your own for the filtration and maintenance of your aquarium water. Along with a flexible interior, the canister filter allows for other devices, like UV sterilizers, heaters and water chillers to be chained in-line.
This way, all the water treatment happens behind the scenes and clean, finished water returns to the tank from a single outlet. However, if this complicated system isn’t cleaned properly, the canister can quickly turn into nitrate factories, so make sure you can commit to cleaning before contemplating a chained configuration.
They get water cleaner
. There’s no doubt that the water that comes from a canister filter contains fewer fine particles than water filtered by an HOB. The larger capacity of the canister allows for additional stages of filtration unavailable in an HOB and increased filtration material surface area means a larger biofilter can be established.
They can be used to create an equipment-free appearance
. Because of their ability to link other devices together in-line, canisters can create a more natural environment for your fish. Instead of many different pieces of internal equipment, your fish will only have the input and the output to the canister to contend with. This can be useful if space is at a premium in your tank or you simply don’t want to see all your aquarium equipment.
. Although many HOB enthusiasts would argue that they love the sound of their filters, canister filter fans do not. With a canister, there’s no constant trickle, no hum of the motor – all you hear is silence. With the canister below your tank and inside a cabinet, any motor sounds you might hear are dampened – and provided you’re keeping your tank reasonably full, you’ll not even hear the splash of the outlet pipe.
There are lots of ways to keep a clean tank, but when you’re shopping for the most popular equipment in the hobby, you’ll be faced with a choice between a HOB filter and a canister. If you need a workhorse that’ll get the job done for very little investment, the HOB is the clear winner, but if you’d rather customize your filter, then pick up a canister. In the end, there’s no wrong answer as long as you can maintain the conditions your fish require to thrive.