OASE BioMaster 2 Thermo 600 External Filter with HeatUp 300 review

Bottom line: the OASE BioMaster 2 Thermo 600 is a US external canister configuration (SKU 94681) sold with a HeatUp 300 heater. Its separate, removable pre-filter and included heater are useful distinctions on paper; its advertised 160-US-gallon ceiling is not a complete tank-size range or a stocking guarantee. This is a source-based assessment, not a hands-on test.

What the Thermo 600 includes

OASE identifies this as a BioMaster 2 Thermo external filter and lists HeatUp 300, 300 W, as included. The maker's parts list separates the canister/filter body (SKU 94702) from heater SKU 33805, while the full Thermo unit has its own SKU, 94681. That is a functional package difference, not a reason to merge it with the standard BioMaster 2 600 review: the standard configuration does not include that heater. If a listing calls itself only “BioMaster 600,” check the exact item number and the box rather than assuming the heater is present.

The manufacturer describes a priming button, a removable EasyClean pre-filter, foam media and Hel-X biological media in a staged flow path. The pre-filter can be lifted out separately from the main filter module; OASE also describes shutoff/safety features intended to limit spills during service. These are design claims, not proof of a particular cleaning interval or a measured reduction in maintenance. The published 6.8 L figure is called filter volume and 0.60 L is called pre-filter volume. Neither is identified as media-basket capacity, so neither satisfies the site's basket-litres comparison.

Placement and installation checks

“External-only” does not mean that it must sit under the stand. The official North American operating manual names SKU 94681 in its applicable-item table and says to install the canister next to or under the aquarium, while noting maximum head height. The 600 body is listed at 9.4 × 9.4 × 19 inches and the kit includes a 13-foot hose; those dimensions do not by themselves establish a safe route or service clearance. Before choosing a beside-tank location, check the current model-specific head instruction, support, hose bends, electrical drip loops and room to withdraw the pre-filter. A nearby shelf is not automatically a suitable location just because the manual permits next-to placement.

The US manual's North American section lists 120 V / 60 Hz, 23 W filter draw, a 300 W heater for Thermo, and allows both freshwater and saltwater use. The exact product route separately shows “22 + 300 W” for filter plus heater even though its standalone filter field says 23 W; that inconsistency is retained rather than silently totalled or reconciled. Match the electrical label and source documentation to SKU 94681, not to an international BioMaster page.

Capacity and the limits of a volume label

OASE's current US item page describes this configuration for aquariums up to 600 litres and lists a maximum of 160 US gallons. The SKU-specific North American manual calls 160 gallons / 600 litres a recommended aquarium volume. A maximum and a single recommendation are not a manufacturer-stated lower-to-upper interval. The matcher therefore cannot certify the Thermo 600 for an exact entered tank volume from this evidence alone; that is a conservative data boundary, not a claim that the filter cannot operate in a smaller tank.

That distinction matters for unusual livestock loads as well. Neither a capacity ceiling, the filter-volume figure nor a heater's wattage establishes fish count, waste-processing rate, turnover under a real installation, or species-appropriate current. No model-specific high-waste suitability statement was found in the reviewed OASE materials. Plan filtration around the actual aquarium and care routine, and seek qualified husbandry advice where the load is atypical rather than treating this filter's size label as a stocking prescription.

Published flow figures and competing configurations

There is a material source discrepancy in the hydraulic figures. The exact US product-page technical route reports 345 gallons per hour / 1,320 L/h and 5.9 feet / 1.8 metres maximum head. The applicable US manual lists 350 gallons per hour / 1,250 L/h and 6.6 feet / 2.0 metres for the 600 size. Both are OASE evidence tied to the family, but the values are not identical; this assessment does not select one as a settled performance number or use either for a cabinet match. The manual's recommendation is likewise not a measured aquarium result.

The nearest comparison is the standard BioMaster 2 600: it shares the 600-size filtration platform but omits the included HeatUp 300. Thermo 600 may suit someone who wants the filter-plus-heater package and can verify the heater is the correct part; it is not automatically the better filter. The Thermo 350 includes a smaller 200 W heater, and Thermo 850 includes a 400 W heater; their body sizes and unresolved flow details differ. Compare the exact SKU and review rather than selecting only by the “600” label.

Who should keep it on the shortlist?

Keep the Thermo 600 in consideration when an external canister and an included 300 W HeatUp are both relevant, and when the planned next-to-or-under position can meet the exact installation requirements. Its useful on-paper features are the serviceable pre-filter, included heater, listed filter media and clear US SKU. Its decision limits are equally important: no sourced lower tank-volume endpoint, no basket-capacity figure, no documented high-waste rating, and conflicting official flow/head and combined-power values.

Before buying, confirm that the unit is US SKU 94681, verify HeatUp 300 and the exact accessory/media contents, read the applicable US filter and heater instructions, and measure clearance around the 19-inch body, hoses and removable pre-filter. A seller's bundle or a similarly named standard SKU may differ. We do not claim current stock, price, personal ownership, aquarium results or product testing.