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. This article will teach you how to optimize an aquarium filter with just a pair scissors.

Step 1: Get 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 sponge is a cylindrical foam that fits over your intake tube for your hang-on or canister filter. It looks like a shoe on 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: Dispose of the Disposable Cartridge

We have already mentioned at the start of this article that you need to replace the standard cartridge with which the filter came. Why is this so terrible? It is true that cartridges are mostly made of fine filter pad for mechanical filtration (to remove any debris from the water), with activated charcoal inside for chemical and filtration (to remove medicines and other impurities). Unfortunately, activated and fine filter carbon quickly absorb impurities and become very difficult to clean.

Step 3: Install the Reusable filter Media

The filter compartment, where the cartridge was supposed to be placed, should be filled with bio rings and coarse foam sponge. 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. Because they are not easy to clog, can last for 10 years, and are relatively inexpensive, we offer coarse sponges. Bags of bio rings with lots of pores for beneficial bacteria can be used to filter biological waste. If the bag does not fit into the filter well, you can purchase a resealable media bag that contains enough bio rings to fill the entire filter.

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

To install the filter media, determine the direction in which the water flows through it. For example, in an AquaClear filter, the water travels upwards from the bottom of the filter compartment to the top and then falls 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. That way the coarse sponge removes most of the gunk from the water and the bio rings (which has smaller pores) won’t get dirty as quickly.

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. We recommend replacing the disposable cartridge with coarse sponge. This provides both mechanical and beneficial filtering.

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. These fine filter pads, like the cartridges will eventually have to be thrown away and replaced when they are clogged with debris. However, the advantages are these pads are very cheap 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.

Last Thoughts

Reusable filter media can make your aquarium system more efficient and help maintain high water quality. While the initial cost of reusable filter media may seem higher, it will last the entire lifetime of your filter, which can save you significant money over time.