Bio Media: 9 Helpful Answers You Should Know (For Beginners)

As you start with your tank’s setup, one of the most important in your list is proper filtration.

Bio (biological) media is one of the suggested filter media to maintain the nitrogen cycle in your tank. So, what is biomedia, and how can it help in the filtration system?

What Is Bio Media?

Bio media is any unmoving object that provides shelter to good bacteria that play an important role in the nitrogen cycle.

Bio media is one of the safest methods in keeping your tank clean. It is purifying water through natural ways, thus, many fish enthusiasts prefer adding this to their tank.

Bio media is one of the three major types of filter media along with mechanical media and chemical media. It offers a larger and safe spot for beneficial bacteria where they can fully grow and multiply.

These bacterias are breaking down any kind of harmful contents so they can be less noxious for your fish. They are providing nutrients and oxygen once the water passes through them, which is required for a successful nitrogen cycle.

Do You Need Bio Media?

No, you do not necessarily need bio media. But having one offers great benefits for improving the filtration system in your tank.

Even with no bio media, your tank inhabitants will do fine. Bio media is simply an additional tool that will help you purify the water in your tank. 

Do not worry too much about not having bio media as there are still other beneficial options in ensuring that your aquatic pets are breathing the most suitable water for them.

A bio media is highly recommended if you have a heavy load tank to assist in the water filtration. With more fish and corals, you also need to remove more ammonia, nitrite, and nitrate.

Bio media is an effective way to cultivate good bacterias that will keep the tank’s water clean and safe.

Can I Use Lava Rock As Bio Media?

Yes, you can use lava rock as bio media. It is a great filter media alternative as it offers more surface area where good bacterias can flourish.

With lots of bio media options in the market, you might consider using lava rock. Perhaps because it is being molded most naturally giving it a positive edge over other media.

Lava rock is the hot lava from an erupting volcano that cools and solidifies. It is highly porous and has holes/cracks which are essential characteristics of bio media.

It is a preference as bio media because of its large surface. The bigger the surface of a filter media, the better because it is particularly favorable for beneficial bacterias. They will grow efficiently on it given that it is not round nor smooth.

Yet, you should be well-informed of lava rock’s drawbacks before actually placing one in your aquarium.

It is beneficial to have a porous rock however, over time, the holes and cracks on it will be clogged with wastes and detritus. These gaps are quite difficult to clean which will lessen the valuable surface of the rock eventually.

Lava rock could potentially increase the pH level of your tank’s water based on how much you utilize it. Still, you should be cautious as lava rock carries minerals that can make the water harder, creating difficulties in managing algae blooms.

Do You Need To Replace Bio Media?

Yes, you need to replace bio media. It gets clogged or damaged over time so you need to make replacements to ensure always having a clean surface for efficient bacteria buildup.

The need for bio media replacement depends on the types that you have. Some require periodic changing, some can be cleaned and reused, while others just demand replacement once damaged.

The usual kinds of bio media that need regular replacement are clay rings, sintered glass, ceramic balls, and lava rock. It is because they are porous solid – they will eventually get dirty and clogged, which is hard to flush out.

The replacement of bio media also depends on the brand that you have.

Fluval Bio-Max is recommended to be replaced every six months, but not all at one time since it would disturb the good bacteria. Eheim Ehfi Substrat Pro Filter Media is advised to replace every filter cleaning but only 1/3 of it. Meanwhile, Marineland Ceramic Bio-Rings only need to be replaced once it is broken, either partially or entirely.

How Much Bio Media Do I Need?

The amount of bio media that you need depends on your tank’s size and load – the more loaded your tank is, the more bio media you need. Checking the water parameters will give you an idea of whether you have enough or still lack bio media.

There is no standard amount required when it comes to adding bio media to your tank. It would highly depend on the number of aquatic inhabitants and the size of your aquarium.

If you have a loaded aquarium, you can expect a lot of waste and toxins in the water. With this, you need more bio media to cultivate more good bacteria that will help in breaking down these harmful pollutants and to better filter the water.

Additionally, you may check the water parameters to see if you have ammonia and nitrites. If you have zero ammonia and nitrites, then you have enough bio media. If the numbers surge, then you need to add more.

Can You Have Too Much Bio Media?

Yes, you can have too much bio media. Extra media will be helpful in any case you need to increase filtration. Yet, you should be aware of the drawbacks of having excess media.

Having too much bio media can provide support if ever your tank will be needing an increased filtration. This will be required as the fish grow since they will produce more wastes.

If you are planning to add more fish in the future, having an excess of this media is an advantage since you will have a mature tank that is prepared for new inhabitants. Enough good bacteria to extract toxins will be present already as an increasing population means more rubbish.

However, you must be mindful of the cons of having too much media too.

One is the increase in maintenance as more bio media means more cleaning. Excess in this media can also reduce the visual appeal of your tank. It will also take too much space, leaving less room for fish to swim.

Do You Rinse Bio Media?

Yes, there are bio media that can be rinsed. You can wash them if they get too covered with dust and debris. Yet, some types are not advised to be rinsed and reused and are better to be replaced with new ones.

Not all bio media are the same. They are made with different materials by various manufacturers, hence they have separate maintenance processes.

For instance, bio media like ceramic rings and bio-balls should be rinsed regularly especially if they are already loaded with lots of debris. Without the appropriate maintenance, they will be producing lots of nitrates.

When rinsing bio media, it is recommended to use the old tank water that is then treated to keep the good bacteria alive. If you prefer using tap water, you can add some drops of water conditioner to remove chlorine and chloramine, and even detoxify ammonia, nitrite, and heavy metals.

Can I Put Bio Media In Tank?

Yes, you can put bio media in the tank. It will not be productive without some water flowing through it.

If you are new to bio media, you might have questions regarding where to perfectly put it. You may see a couple of bio media placed outside of the main tank; but before, these filter media were only placed inside the tank.

You can definitely put it inside the tank which is typically placed between the mechanical media and chemical media. They should be ordered as mechanical media first, then bio media, then chemical media as last.

You need to put your bio media inside the tank so water will flow through it. Your media simply needs currents so the bacterias colonizing it will get enough oxygen, preventing any worst scenario that can even lead to their death.

You can even add a small powerhead to guarantee the adequate flow of water to the bacteria.

Bio Media VS Sponge

Bio media is used for housing beneficial bacterias that assist in the nitrogen cycle while the sponge is used in mechanical media to capture debris.

Bio media is one of the three types of filter media while the sponge is usually a part of mechanical media, which is also one of the filter media.

Bio media is assisting in the filtration system by housing bacteria that break down water pollutants that are usually fish’s waste.

Meanwhile, the sponge is placed in mechanical media to filter the water by blocking the debris and other wastes. It is physically straining the water so wastes will be collected and stay in the mechanical media.

Bio Media

When looking for a perfect bio media, you may be overwhelmed with the numerous selection in the market. Below is the list of the top bio media that both beginners and experts in tank keeping can consider to check and buy eventually.


Hauter, S., & Hauter, D. (2019, June 23). How To Clean Dirty Bio-Balls. The Spruce Pets.

LiveAquaria. (2021). The Basics Of Aquarium Filtration. LiveAquaria | Quality Aquarium Fish, Supplies & Equipment.

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