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. We will show you how to optimize your aquarium filter using just a pair of scissors.

Step 1: Purchase 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 can grow on any surface underwater, even the gravel or walls of your aquarium. A prefilter sponge is one of the best ways to encourage their 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.

Place the prefilter sponge in a position that covers the intake tube’s slits. The filter will draw water from the sponge’s bottom for maximum filtration. To make it more snug, cut off some of the prefilter sponge. If you notice a decrease in the flow of water through your filter, it is important to clean it at least once per month.

Step 2: Dispose of the Disposable Cartridge

At the beginning of the article, we mentioned that you should replace the default cartridge the filter comes with. It is so bad, you ask? The fact is that most cartridges are made out of fine filter padding for mechanical filtration (to remove debris from the water) with activated carbon inside for chemical filtration (to remove medications and other impurities from the water). Unfortunately, the fine filter padding and activated carbon quickly become saturated with waste and impurities, greatly lowering their effectiveness, and their dense materials are hard to clean and reuse.

Step 3: Install 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! As with the prefilter sponge, there is no need to constantly replace them and throw away all that beneficial bacteria; just rinse the filter media in old aquarium water once a month.

Coarse sponge pads remove debris from the water and can be reused by rinsing them 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. For biological filtration, you can use bags of bio rings that have lots of porous holes for beneficial bacteria to grow in. 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.

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 on the bottom of the compartment, so that the water hits it first. Then place the bio rings above 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?

You can polish your water by adding a thin layer of poly pad with very small pores that can remove tiny particulate. These fine filter pads, like the cartridges will eventually have to be thrown away and replaced when they are clogged 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.

Last Thoughts

Upgrading your filter with reusable filter media makes your aquarium system much more efficient and better at keeping the water quality high. The upfront cost may be a little more at first, but reusable filter media tends to last for the lifetime of the filter, saving you a lot of money in the long run.