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Which HMU option is documented as 300 W?
The official Finnex Shop lists a 300 W HMU choice with SKU HMU-300S and its own Shopify variant ID. Its official variant barcode field is blank, so the UPC is unverified.
Explore this need in the finder →Does Finnex publish a tank-size range for HMU 300 W?
Not in the primary Shop record or the reviewed comparison chart. The chart gives a 100–500 W family span but no capacity band. Do not turn 300 W into a gallon recommendation; this variant remains reference-only.
Explore this need in the finder →What control range can be attributed to HMU 300 W?
Finnex’s comparison chart lists a shared 68–92°F HMU range for its 100–500 W span. This is a manufacturer claim, not an independently measured water temperature; the product still lacks a supported tank capacity and setup.
Explore this need in the finder →Finnex HMU digital titanium series · 300 W · reference-only assessment
Finnex's official Shop page identifies a distinct 300 W HMU choice as SKU HMU-300S, with its own variant record. The official comparison chart includes 300 W in the stated 100–500 W HMU range and lists several capabilities shared across that band. Neither primary source says what aquarium volume this exact 300 W variant is rated for. Without that basic sizing evidence, assigning it to a tank or showing it as a finder answer would turn the wattage label into an unsupported capacity claim.
What the maker says about this series
The grouped Shop description identifies a titanium tube, remote temperature sensing, adjustable digital controller/display, flame-retardant protective guard and a non-resumable fuse for an exposed heating element. For HMU 100–500 W, the comparison chart also lists a steel coil, push controls, digital display, a 68–92°F range and Japanese components. Those descriptions support a reference-level account of the controls and construction, not an independent assessment of precision, service life or protective performance. They do not resolve which exact installation arrangement is allowed.
Position among the listed wattages
HMU-300S is the 300 W choice in a six-option ladder: 100, 200, 300, 400 and 500 W are all charted, while the separate 50 W variant is not. A 300 W rating distinguishes its nominal power from the adjacent models, but the sources do not give tank-volume boundaries or heater dimensions for any of these options. I therefore cannot say that it is “for” a particular gallon size or select it over a smaller or larger wattage based on a documented aquarium-use range. Factors such as actual water volume, room temperature, water movement and cover need a supported sizing basis, not a guessed watt-to-gallon conversion.
Evidence gaps that prevent a buying shortlist
The source set does not verify a full voltage/frequency rating, barcode, dimensions, water-type support, full immersion and clearance directions, or an HMU-specific instruction document. The Finnex instructions index names several other heater manuals but not HMU; other product families are not substitutes. The official Shop gallery is a shared series gallery rather than a visibly labeled 300 W model image, so it is not presented as exact-model photography. The Shop listing's sold-out state is only a retrieval snapshot; no availability, price or lifecycle claim is made here. Until a seller supplies the exact HMU-300S package and its instructions, this item remains a reference-only identification, excluded from matching and BuyerShortlists purchase landings.
Evidence checked
Primary sources: the Finnex Shop HMU variant record, the Finnex comparison chart and the Finnex instructions index. This page reports no hands-on testing.
Key specifications
Key details at a glance
| Rated heater power | 300 W |
|---|---|
| Lowest thermostat setting | 68°F |
| Highest thermostat setting | 92°F |
| Temperature control | Adjustable thermostat |
Use the exact model’s instructions for operating limits, supplied equipment and version differences.
Sources for this review
Sources for this assessment
Check the complete aquarium setup
Use the finder to compare documented tank size, water type, installation and temperature-control fit. A match does not guarantee the keeper's species-specific target or measured performance.