Choosing the right external filter can make a major difference to the stability, clarity and long-term health of your aquarium. For planted tanks and aquascapes, two excellent options are the OASE BioMaster² and the AquaEL Ultramax BT.
Both are powerful canister filters designed for serious aquarium keepers, but they are not exactly aimed at the same type of aquarist. The OASE BioMaster² is ideal if you want premium build quality, easy pre-filter maintenance and, in the Thermo versions, the clean look of an integrated heater. The AquaEL Ultramax BT is the better choice if you want a very large media capacity, Bluetooth control and flexible flow adjustment from your phone.
In this guide, we compare both filters to help you choose the best external filter for your planted aquarium, aquascape or community tank.
Quick Recommendation
Choose the OASE BioMaster² if you want a refined, quiet and easy-to-maintain external filter with excellent mechanical and biological filtration. It is especially suitable for aquascapes where you want a clean layout, stable flow and simple pre-filter access.
Choose the AquaEL Ultramax BT if you want more digital control, a very large filter chamber and the ability to adjust flow patterns, feeding mode and day/night operation through the AquaEL BT app.
Comparison Table: OASE BioMaster² vs AquaEL Ultramax BT
| Feature | OASE BioMaster² | AquaEL Ultramax BT |
|---|---|---|
| Best for | Premium planted tanks, aquascapes and users who value easy maintenance | Aquarists who want Bluetooth control, large media capacity and adjustable flow |
| Flow rate | Depending on model, up to 900–1500 litres per hour | High-performance external filter with app-adjustable flow |
| Media capacity | Strong filter volume depending on model, with Hel-X and sponges | Very large media capacity, up to 10.1 litres including pre-filter |
| Pre-filter | EasyClean pre-filter module | Integrated pre-filter in the filter lid |
| Smart control | No Bluetooth control | Bluetooth control through the AquaEL BT app |
| Heater option | Available in Thermo versions with integrated heater | No integrated heater in the standard Ultramax BT filter |
| Maintenance style | Very simple pre-filter cleaning without dismantling the whole filter | Easy access to the pre-filter and flexible basket arrangement |
| Best aesthetic advantage | Thermo versions reduce visible equipment inside the aquarium | Digital control allows flow adaptation without manually adjusting the filter |
OASE BioMaster²: Best for Clean Aquascapes and Easy Maintenance
The OASE BioMaster² is a premium external filter designed for aquarists who want powerful filtration without making maintenance complicated. One of its strongest features is the EasyClean pre-filter module. Instead of opening the entire canister every time you need to remove coarse dirt, you can simply remove and rinse the pre-filter module.
This is a major advantage in planted aquariums. Aquascapes often collect small plant leaves, fine debris, shrimp waste and organic particles from trimming sessions. A filter that allows quick pre-filter cleaning helps maintain stable flow without disturbing the biological media too often.
The BioMaster² also uses a combination of biological filtration with Hel-X and mechanical filtration through sponges. This makes it a strong option for aquariums where water clarity, biological stability and consistent circulation are important.
Why Aquascapers Like the OASE BioMaster²
In an aquascape, equipment should support the layout without becoming visually distracting. The OASE BioMaster² Thermo versions are especially useful because the heater is integrated into the filter. This reduces the amount of visible equipment inside the aquarium and helps create a cleaner, more natural-looking display.
For planted tanks with CO2 injection, stable flow is also important. Good circulation helps distribute CO2, nutrients and heat more evenly around the aquarium. The BioMaster² is a good choice for aquarists who prefer reliable performance and straightforward maintenance rather than app-based settings.
AquaEL Ultramax BT: Best for Smart Flow Control and Large Media Capacity
The AquaEL Ultramax BT is a modern external filter designed for aquarists who want more control. Its main advantage is Bluetooth connectivity through the AquaEL BT app. This allows you to adjust the filtration level and flow behaviour directly from your phone or tablet.
The Ultramax BT is also very strong in terms of media capacity. With five large media baskets and an integrated pre-filter, it can hold a large amount of mechanical and biological filter media. This makes it a powerful option for larger aquariums, demanding community tanks or aquariums with a heavier fish load.
Another benefit is its flexible flow control. You can set different circulation modes, reduce flow during feeding and adjust day/night operation. This is particularly useful if you keep fish that prefer calmer water at night or if you want more control over surface movement in an open aquarium.
Why the AquaEL Ultramax BT Stands Out
The Ultramax BT is not just a strong filter; it is a smart external filter. The app-controlled flow makes it easier to adapt the filter to different aquarium situations without reaching into the cabinet or manually adjusting valves.
This is useful for aquarists who like to fine-tune their setups. For example, you may want stronger circulation during the day when plants are photosynthesising and a softer flow during the night. You may also want to reduce flow temporarily during feeding so fish can eat comfortably without food being pushed around the tank too quickly.
Which Filter Is Better for a Planted Aquarium?
For most planted aquariums, both filters can work very well. The best choice depends on how you manage your tank.
If your priority is a clean aquascape, easy maintenance and minimal visible equipment, the OASE BioMaster² Thermo is probably the better option. The integrated heater option is especially attractive for aquascapers who want to keep the aquarium as clean and natural-looking as possible.
If your priority is media capacity, flexible flow and smart control, the AquaEL Ultramax BT is a very strong choice. It gives you more control over circulation and allows you to adjust the filter according to the behaviour of your fish, feeding routine or planted tank schedule.
Which Filter Is Easier to Maintain?
The OASE BioMaster² is excellent for simple routine maintenance because of its EasyClean pre-filter system. This allows you to clean the part of the filter that collects most coarse debris without opening the entire canister.
The AquaEL Ultramax BT is also maintenance-friendly. Its integrated pre-filter can be accessed from the lid, and the double shut-off valve system helps reduce water spills when disconnecting the filter. It also gives you large media baskets, making it easy to customise media layout for mechanical, biological or chemical filtration.
If you want the simplest pre-filter routine, the OASE BioMaster² has the advantage. If you want more space and more media flexibility, the AquaEL Ultramax BT is the stronger option.
Which Filter Is Better for Larger Aquariums?
For larger aquariums, the AquaEL Ultramax BT has a clear advantage in media volume. Its large internal capacity makes it suitable for aquariums with a higher biological load, such as community tanks, discus tanks or larger planted layouts.
The OASE BioMaster² is available in different models, so it can also be matched to medium and large aquariums. However, the Ultramax BT is particularly attractive if your main concern is maximum filter media capacity and adjustable performance in one unit.
Which Filter Is Better for Aquascaping?
For aquascaping, the OASE BioMaster² Thermo is usually the more elegant choice. The integrated heater option keeps the inside of the aquarium cleaner, which is important when the visual impact of the layout matters.
That said, the AquaEL Ultramax BT can also be excellent for aquascapes, especially larger layouts that need strong but adjustable circulation. The ability to reduce or change flow through the app can be useful when balancing plant movement, CO2 distribution and fish comfort.
Recommended Choice by Aquarium Type
| Aquarium Type | Recommended Filter | Reason |
|---|---|---|
| Clean aquascape display | OASE BioMaster² Thermo | Integrated heater and simple maintenance |
| High-tech planted tank | OASE BioMaster² or AquaEL Ultramax BT | Both offer strong flow and good biological filtration |
| Large community aquarium | AquaEL Ultramax BT | Large media capacity and adjustable flow |
| Tank with heavy fish load | AquaEL Ultramax BT | More space for biological and mechanical media |
| Aquarium where visual equipment should be minimal | OASE BioMaster² Thermo | Reduces visible equipment inside the tank |
| User who enjoys app-based control | AquaEL Ultramax BT | Bluetooth control through the AquaEL BT app |
Final Verdict: OASE BioMaster² or AquaEL Ultramax BT?
The OASE BioMaster² is the best choice for aquarists who want a premium external filter with excellent maintenance convenience, quiet operation and the option of an integrated heater. It is particularly well suited to aquascapes and planted aquariums where aesthetics matter.
The AquaEL Ultramax BT is the best choice for aquarists who want high media capacity, smart flow control and modern Bluetooth functionality. It is especially useful for larger aquariums, high-bioload tanks and users who want more control over filtration throughout the day.
If you are still unsure, the safest rule is simple: choose the OASE BioMaster² for clean aquascaping convenience, and choose the AquaEL Ultramax BT for smart control and maximum media flexibility.
You can explore both options in our external aquarium filters category.
Frequently Asked Questions
Is the OASE BioMaster² better than the AquaEL Ultramax BT?
Not always. The OASE BioMaster² is better if you want easy maintenance, premium build quality and the option of an integrated heater. The AquaEL Ultramax BT is better if you want Bluetooth control, very large media capacity and adjustable flow modes.
Is the AquaEL Ultramax BT good for planted aquariums?
Yes. The AquaEL Ultramax BT is suitable for planted aquariums, especially larger setups that need strong filtration and flexible flow control. Its large media capacity is useful for biological stability.
Is the OASE BioMaster² good for aquascaping?
Yes. The OASE BioMaster² is an excellent option for aquascaping, especially the Thermo versions with integrated heater. This helps reduce visible equipment inside the aquarium and keeps the layout cleaner.
Which external filter is easier to clean?
The OASE BioMaster² has a very convenient EasyClean pre-filter module, making routine maintenance simple. The AquaEL Ultramax BT is also easy to maintain, with an accessible pre-filter and double shut-off valve system.
Which filter should I choose for a large aquarium?
For larger aquariums or tanks with a heavier fish load, the AquaEL Ultramax BT is a strong choice because of its very large media capacity and adjustable performance. The OASE BioMaster² is also available in different sizes and can be matched to medium and large tanks.
