How to Upgrade an Aquarium Filter (and Save Money!)

Have you ever bought a new hang-on-back filter from the pet store and noticed that the instructions say you have to change out the filter cartridge at least once a month? Most beginner fish keepers don’t realize that you can replace those disposable cartridges with reusable filter media that can last for the lifetime of the filter. In this article, we teach you how to optimize your aquarium filter in four simple steps, using only a pair of scissors.

Step 1: Buy a Prefilter sponge

Beneficial bacteria are a naturally occurring form of biological filtration that consume the toxic nitrogen compounds produced by your fish’s waste, thus making the water safer for the fish to live in. They will grow on any type of underwater surface, including gravel and walls. Prefilter sponges are a great way to encourage them growth. (If you aren’t familiar with the three types of filtration – mechanical, biological, and chemical – you can read our article called Fish Tank Filters: Which One Should You Get?)

Prefilter sponges are a foam cylinder that fits around the intake tube of your canister or hang-on back filter. It is similar to a sock for a foot. Not only do prefilter sponges grow lots of beneficial bacteria, but they also help with mechanical filtration by preventing food, small fish, leaves, and other large debris from getting sucked into the filter’s motor compartment.

Pick an appropriately sized prefilter sponge for your filter, and you can easily double its filtration capacity.

Install the prefilter sponge so that it barely covers the slits on the bottom of the intake tube; that way the filter pulls water from the bottom of the prefilter sponge for maximum filtration. If your prefilter sponge seems a bit loose, you can trim the excess and stuff it into the hole in the middle. You should also make sure that you clean your prefilter sponge at least once a month if the water flow is declining.

Step 2: Remove the Disposable Cartridge

At the beginning of the article, we mentioned that you should replace the default cartridge the filter comes with. But why is it so bad? Most cartridges are made from fine filter padding to remove water debris and activated carbon for chemical filtration. This is used to remove drugs and other impurities. Unfortunately, activated carbon and fine filter padding quickly get clogged up with impurities and waste, reducing their effectiveness. Also, their dense materials can be difficult to clean and reuse.

Step 3: Install Reusable Filter Media

Fill up the filter compartment (where the filter cartridge was supposed to go) with coarse foam sponge and bio rings. These filter media types are reusable, have much more surface area for biological filtration, and can increase the amount of capacity filtration by up to four times! The prefilter sponge is not necessary to be replaced and all the beneficial bacteria can be thrown away. Instead, rinse the filter media with old aquarium water once a monthly.

Coarse spongy pads can remove any debris from water and can be used again by rinsing on a monthly basis.

For mechanical filtration, we like to use coarse sponge pads that you can cut to fit any compartment in a hang-on-back or canister filter. We offer coarse sponges because they do not clog very easily, are fairly low cost, and can last 10 years or more. You can also use bio rings bags that have many porous holes to allow beneficial bacteria to grow. You can use a resealable bag to fit the bag into the filter.

Bio rings help boost the growth of biological bacteria, which consume the toxic nitrogen compounds produced by fish waste.

In order to install the filter media, find out which direction the water flows through the filter. AquaClear filters, for example, allow the water to flow upwards from the bottom to the top of the filter and then back into the aquarium. Place the coarse sponge pad at the bottom of the compartment (so that the water hits it first), and then place the bio rings on top of the sponge. The coarse sponge will remove most gunk from the water, and the bio rings with smaller pores won’t become as filthy.

If you have a nano tank for your betta fish that comes with a built-in filter compartment, you may not be able to fit as many layers inside. The disposable cartridge should be replaced with coarse sponge. This will provide both mechanical and beneficial filtration.

Step 4: Clean the Reusable Filter Media

Regular maintenance is important. Rinse the filter media at least once per month. Mechanical filtration (such as prefilter sponges and sponge pads) acts like a garbage can that collects waste – which means you as the fish owner are still responsible for cleaning the filter media (in other words, “emptying” the trash can before it overflows and causes water to spill out of the aquarium).

How do I upgrade my filter to get crystal clear water?

If you want to really polish the water, simply add a layer of fine poly pad that has very small pores and is capable of removing tiny particulate. Like the cartridges, these fine filter pads will eventually need to be thrown out and replaced once they become saturated with debris. The advantages of these filters are that they are inexpensive and can be cut to any size.

Poly pads are great at removing fine particles so that you get crystal-clear water and your fish look like they’re flying in midair.

Final Thoughts

Upgrading your filter with reusable filter media makes your aquarium system much more efficient and better at keeping the water quality high. Although it may cost more upfront, reusable media can last for many years, which will save you lots of money over the long-term.