Oase External Filters

At Charterhouse Aquatics, we’re proud to offer the full range of Oase External Filters—engineered for aquarists who want crystal-clear water and easy, reliable maintenance. From the compact FiltoSmart to the advanced BioMaster and BioMaster² Thermo with integrated heating, each model delivers superior multi-stage filtration and hassle-free cleaning. Using a combination of Hel-X media, sponge filtration, and the innovative EasyClean pre-filter, Oase ensures healthy, stable water conditions for tanks of all sizes. Expand below to explore the features, benefits, and find the perfect filter for your aquarium.

At Charterhouse Aquatics, we’re proud to offer the full range of Oase External Filters—engineered for aquarists who want crystal-clear water and easy, reliable maintenance. From the compact FiltoSmart to the advanced BioMaster and BioMaster² Thermo with integrated heating, each model delivers superior multi-stage filtration and hassle-free cleaning. Using a combination of Hel-X media, sponge filtration, and the innovative EasyClean pre-filter, Oase ensures healthy, stable water conditions for tanks of all sizes. Expand below to explore the features, benefits, and find the perfect filter for your aquarium.

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 Have questions about Oase External Filters? Checkout out our FAQ!

5 Reasons to Choose Oase External Filters for Easy Maintenance

Keeping aquarium water healthy shouldn’t be a chore. Here’s why Oase external filters are a favourite among aquarists who want crystal-clear results with minimal fuss—plus practical tips to get the... read more
Keeping aquarium water healthy shouldn’t be a chore. Here’s why Oase external filters are a favourite among aquarists who want crystal-clear results with minimal fuss—plus practical tips to get the most from your setup. read less

Setting Up Your Oase BioMaster² Thermo: Step-by-Step

The Oase BioMaster² Thermo is one of the most advanced external filters on the market, designed to combine powerful multi-stage filtration with the convenience of an integrated heater. read more
The Oase BioMaster² Thermo is one of the most advanced external filters on the market, designed to combine powerful multi-stage filtration with the convenience of an integrated heater. read less

Oase vs. Eheim vs. Fluval: Which External Filter Fits Your Tank?

Choosing the right external filter can make or break your aquarium’s long-term success. With so many options available, three brands consistently stand out in aquatics: Oase, Eheim, and Fluval. read more
Choosing the right external filter can make or break your aquarium’s long-term success. With so many options available, three brands consistently stand out in aquatics: Oase, Eheim, and Fluval. read less

5 Reasons to Choose Oase External Filters for Easy Maintenance

Keeping aquarium water healthy shouldn’t be a chore. Here’s why Oase external filters are a favourite among aquarists who want crystal-clear results with minimal fuss—plus practical tips to get the... read more
Keeping aquarium water healthy shouldn’t be a chore. Here’s why Oase external filters are a favourite among aquarists who want crystal-clear results with minimal fuss—plus practical tips to get the most from your setup. read less

Setting Up Your Oase BioMaster² Thermo: Step-by-Step

The Oase BioMaster² Thermo is one of the most advanced external filters on the market, designed to combine powerful multi-stage filtration with the convenience of an integrated heater. read more
The Oase BioMaster² Thermo is one of the most advanced external filters on the market, designed to combine powerful multi-stage filtration with the convenience of an integrated heater. read less

Oase vs. Eheim vs. Fluval: Which External Filter Fits Your Tank?

Choosing the right external filter can make or break your aquarium’s long-term success. With so many options available, three brands consistently stand out in aquatics: Oase, Eheim, and Fluval. read more
Choosing the right external filter can make or break your aquarium’s long-term success. With so many options available, three brands consistently stand out in aquatics: Oase, Eheim, and Fluval. read less

Have Questions About Oase External Filters?
We Have Answers.

Get quick answers to common questions about Oase External Filters

1. What is an Oase external filter?

An Oase external filter is a high-performance canister filter designed to sit outside your aquarium. It draws water from the tank, passes it through multiple stages of mechanical, biological, and optional chemical media, and returns clean, clear water back to your aquarium. Oase filters are popular for their EasyClean pre-filter system and, in Thermo models, their integrated heater.

2. Which Oase external filter is best for my tank size?

The right Oase filter depends on the size of your aquarium and how heavily it is stocked. The FiltoSmart range is designed for small aquariums and nano tanks, generally up to around 100 litres. The BioMaster range is suited to medium and large aquariums, handling up to 600 litres depending on the model. For those who want the latest features, the BioMaster² Thermo series offers improved flow, easier handling, and an integrated heater, with models available for aquariums up to 850 litres. Always check the specifications for your chosen model to ensure it matches your aquarium’s volume and bioload.

3. What is the difference between the Oase BioMaster and BioMaster² Thermo?

The Oase BioMaster is the original external filter series known for its EasyClean pre-filter and modular basket system. The BioMaster² Thermo is the upgraded version, offering up to 25 percent higher flow rates, improved ergonomics, and an integrated heater that eliminates the need for a separate in-tank unit. This makes the BioMaster² Thermo a more advanced option for aquarists who value convenience, efficiency, and a tidier aquarium setup.

4. How often should I clean an Oase external filter?

Most aquarists only need to clean the EasyClean pre-filter every two to four weeks, depending on stocking levels and feeding habits. The main canister, which holds the biological media, typically requires attention every six to ten weeks. When cleaning, it is important to rinse sponges and media in aquarium water rather than tap water to protect beneficial bacteria. Following this routine ensures consistent water flow and stable biological filtration without disrupting your aquarium’s balance.

5. Can Oase external filters be used in marine tanks?

Yes, Oase external filters are suitable for both freshwater and saltwater aquariums. Many marine aquarists use them for mechanical and chemical filtration alongside protein skimmers. The modular basket system makes it easy to add or remove media depending on whether you are running a fish-only marine setup or a reef tank.

6. Are Oase Thermo filters worth the investment?

For many aquarists, the Thermo models are an excellent investment. The integrated heater eliminates the need for a separate heater inside the aquarium, reducing clutter and providing more even heat distribution through the flow of filtered water. This not only improves the appearance of your aquascape but also simplifies equipment management and reduces the number of cables around your tank.

7. Are Oase filters noisy?

Oase filters are designed to run quietly, making them ideal for living rooms, bedrooms, or offices where background noise can be distracting. Any noise at startup usually comes from trapped air inside the canister and disappears once the filter is fully primed. Routine maintenance, including rinsing the pre-filter and checking the impeller, will help maintain silent operation.

8. Where can I buy replacement parts and media for Oase filters?

Replacement parts, such as sponges, pre-filter modules, hoses, and impellers, are widely available at Charterhouse Aquatics. You can also find Hel-X biological media, additional sponges, and Oase HeatUp heaters to upgrade or maintain your filter. Keeping spare parts on hand ensures your filter always runs efficiently without unexpected downtime.

Discover Oase External Filters at Charterhouse Aquatics

Oase external filters are trusted by aquarists worldwide for their powerful multi-stage filtration, quiet operation, and long-term reliability. Whether you’re running a small planted aquarium, a large freshwater community tank, or even a marine setup, Oase filters deliver crystal-clear water with minimal effort. The innovative EasyClean pre-filter module reduces maintenance time, while models in the BioMaster² Thermo series feature an integrated HeatUp heater, keeping your aquarium clutter-free and perfectly regulated.

At Charterhouse Aquatics, you’ll find the full range of Oase BioMaster, BioMaster² Thermo, and FiltoSmart filters, along with replacement sponges, Hel-X biological media, and accessories to keep your system running at its best. Enjoy fast UK delivery, competitive prices, and expert support when you shop with us. Invest in an Oase external filter today and experience a cleaner, healthier, and easier-to-maintain aquarium.