Do Aquarium Plants Need a Filter?

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Planted aquariums look cool. Plus, live plants bring one important benefit— they help keep the water clean longer. It’s easy to see why so many people want to add plants to their aquariums. But you’ll need some know-how and prep first. Live plants need a proper setup to grow and thrive. And the proper setup for aquarium plants can be a controversial topic.

There’s a lot of confusion surrounding planted aquariums. You might find contradicting information. But I’m here to clarify all misconceptions! In today’s article, I cover some common questions such as “Should I add a filter?”, “Should I use an air pump?”, and “What do I need to grow healthy plants?” Keep reading to discover more about the perfect setup and some good alternatives!

Can Aquarium Plants Live Without a Filter?

Yes, aquarium plants can live and even thrive without a filter. But your setup matters. Filters maintain stable water quality and prevent ammonia buildup. With the filter gone, the plants have to do all the water cleaning. You must be sure your plants can meet the filtration demands of a filter-less tank.

The ammonia load is the most important factor to monitor and manage. A filter-free aquarium should be extra-clean if you want your plants (and fish) to stay healthy. Otherwise, the waste and other by-products that accumulate will cause a sudden shift in water quality.

If the plants can’t keep up with the water filtration demands, you’ll notice undesirable side effects. Some of these side effects include stunted growth, withered leaves, nutrient deficiencies, and algae growth. If you have a lot of fish and just a couple of plants, a few things can go wrong:

  • Plants won’t be able to convert all the waste by-products.
  • Fish will get exposed to potentially deadly concentrations of ammonia.
  • Plants will also get damaged due to excess ammonia.
  • Poor water quality and sick plants lead to algae bloom.
  • Algae can further damage your plants by robbing nutrients from the soil and water.

Ideally, a filter-less tank should only have a few fish, snails, or shrimp. The fewer critters in your tank, the less waste to worry about. You should also include a lot of plants to up the filtration power. The easiest set-up would be a plants-only tank.

Do Aquarium Plants Need an Air Pump?

An air pump is highly recommended. If you’re a newbie aquarist, I’d say it is a must. Even if you have no fish in the tank, you still need to provide surface agitation and aeration of the water column. There are two major reasons why aquarium plants do best with an air pump:

Air pumps prevent algae bloom.

Air pumps create bubbles that travel up to the water’s surface. When these bubbles come on top, they break the surface tension. Simply put, air pumps keep the water moving. As you might know, algae thrive in stagnant and warm water. By creating unfavorable conditions, you keep the algae bloom at bay.

Algae and aquarium plants are sworn enemies. Algae proliferate effortlessly, suck up nutrients like a sponge, and ruin the water quality. There’s no place for algae in a planted tank. Plants already compete for resources with one another. No need to add another hungry adversary to the mix.

Air pumps provide much-needed CO2.

Air pumps let the water “breathe”, aka exchange gases. Water movement and surface agitation make it easier for carbon dioxide to seep in. Carbon dioxide (CO2) is especially important for plant growth and health. It’s one of the main nutrients that plants consume to fuel their metabolism.

If there’s no surface agitation, the CO2 in the air can’t enter the water to keep a steady supply of nutrients. If the water remains still, the aquarium plants will eventually consume all the CO2 in the tank. When this happens, the plants will slowly begin to starve and die off.

Note that some people find success keeping planted aquariums without an air pump. But you’ll have to provide liquid CO2 to compensate for the lack of gaseous exchanges. You’ll have to keep an eye out for the algae too!

Can You Have an Aquarium with Just Plants?

Absolutely! Plant-only aquariums are not only doable but also easy to maintain. This, combined with their pleasing appearance makes them popular DIY ornamental pieces. There’s even a name for creating beautiful planted aquariums— aquascaping.

Having a plant-only aquarium is a lot easier than keeping fish or other aquatic creatures. Once you get the setup right, you’ll only need to do small, occasional maintenance tasks. You won’t have to worry as much about pH, temperature, and water quality fluctuations. You certainly don’t have to remember feeding your plants every day.

As a bonus, you have more freedom when choosing the aquarium size and shape. There are almost zero constraints. So, if you want a luscious green nano-tank on your desk or nightstand, this is the perfect opportunity!

Do Plants Act as a Filter in the Aquarium?

Yes. Plants help purify aquarium water, similar to a filter. They take up CO2 and harmful compounds like nitrates and convert them into harmless oxygen. If you have fish, adding plants to the aquarium will take the water quality up a notch. However, plants aren’t a perfect replacement for a filter.

Plants only provide biological filtration. Depending on the number of plants in your aquarium, the biological filtration might not be enough to counteract the bioload produced by fish. Filters are more efficient in a lot of ways. They have more power, and they provide multiple means of filtration.

Filters offer not only biological filtration (ceramic rings or balls), but also chemical filtration (activated carbon), and mechanical filtration. Thus, filters take care of ammonia, nitrates, dissolved waste, and even free-floating food or waste particles. Plants are obviously no match for a filter, especially in a well-stocked aquarium with a high bioload.

What do You Need to Grow Healthy Aquarium Plants?

Like all living things, plants require nutrients and stable conditions. The exact quantity of macronutrients, micronutrients, and the ideal water parameters will depend on the plant species in question. But the same factors are still necessary for the health of all aquarium plants. Here’s a quick checklist of everything you need for healthy plants:

  • Breathable substrate (Soil or gravel work best.)
  • Clean water (A small HOB filter can take care of ammonia and waste particles.)
  • Visible light (You can provide this with a color spectrum LED lightbulb.)
  • Carbon dioxide (You can install an air pump or use liquid CO2.)
  • Micronutrients (You can provide these with root tabs or liquid fertilizer.)
  • Stable temperature (A heater and a thermometer can help you with this.)

Conclusion

Aquarium plants need three main things to thrive— a breathable substrate, nutrients (CO2, light, minerals, etc), and clean water. You have multiple options to achieve each of these things. When it comes to water quality, the filter and the air pump are your best friends.

These gadgets keep the ammonia and CO2 level within healthy ranges. Filters help the plants keep up with the bioload in the tank. Air pumps keep things moving and provide carbon dioxide for your plants to “eat”. However, neither of these two are must-haves.

A plant-only aquarium or small bioload aquarium might not need a filter. You could also forgo the air pump as long as you supplement with liquid CO2. Ultimately, the best setup for your aquarium plants will depend on other factors, such as tank size, number of plants, and how many fish you keep.

avatar I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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