STEP 3: Choosing the Right Filter
This guide is part of Green Chapter’s Beginner Paths: Start A Planted Tank. In this series, we break down the process step-by-step to help you understand how a planted tank works and how to build one with confidence.
Follow the guides in sequence for the best learning experience.
Once you’ve decided on your tank size and whether to use CO₂, the next step is choosing a filtration system that keeps your tank stable.
Filtration is not just about keeping water clear — it directly affects water flow, plant health, and how stable your system remains over time.
What Does Filtration Do?
A filter helps maintain balance in your tank by:
- removing waste and excess particles
- circulating water evenly
- supporting beneficial bacteria that break down toxins
In a planted tank, filtration also influences how nutrients and CO₂ move through the water.
This means the type of filter you choose affects more than just cleanliness — it affects how your entire system behaves.
Two Common Approaches
There are many types of filters available, but for beginners, two common approaches are often seen.
Hang-On-Back Filter (HOB)
- mounted on the back of the tank
- simple and easy to install
- suitable for basic setups
- creates more surface movement
Because of this surface movement, CO₂ tends to escape more quickly from the water.
Totto-Style Filtration System
- mounted over the back edge of the tank
- designed specifically for planted tank setups
- uses a controlled inlet and outlet pipe system
- provides gentle, even water flow
- minimizes unnecessary surface disturbance
This allows better CO₂ retention and creates a more stable environment for plant growth.
What Happens If You Choose Wrong
Using the wrong type of filtration for your setup can lead to:
- CO₂ being lost too quickly in high-tech systems
- uneven water flow affecting plant growth
- unstable conditions over time
For example, combining a CO₂ system with excessive surface agitation can reduce its effectiveness, making plant growth harder to maintain.
What Should You Choose?
Your choice depends on how your tank is set up.
- If you are running a no-CO₂ (low-tech) tank, a simple HOB filter can work well
- If you are running a CO₂ (high-tech) tank, a more controlled system like a Totto filter is the better choice
The goal is not to pick the “best” filter, but to choose one that supports your system.
How This Affects Your Next Decisions
Your filtration setup influences:
- how evenly nutrients and CO₂ are distributed
- how stable your water conditions remain
- how your plants grow over time
A stable system makes everything else easier — from lighting adjustments to plant care.
What’s Next
With your filtration in place, the next step is to support plant growth properly.
That starts with choosing the right lighting.
👉 Continue to the Next Step
Understanding Aquarium Lighting →
