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Which HMC configuration is mapped to 20–30 gallons?
Finnex assigns HMC-100S, 100 W, to 20–30 US gallons and lists an 8-inch tube. Its Shop variant uses SKU HMC-100S. The lower capacity limit is meaningful and is not represented by the live finder.
Explore this need in the finder →Can the HMC-100S setting be changed?
The family source describes an illuminated digital controller with adjustments, real-time remote-temperature display, a 68–92°F range and memory of the last setting following a power interruption. No independent accuracy measurement is claimed.
Explore this need in the finder →What should be verified before using HMC-100S in saltwater?
Finnex’s family copy says the titanium HMC is for freshwater and marine environments and calls it submersible. It does not give a detailed immersion/waterline or mounting procedure; check the exact package and instructions before setup.
Explore this need in the finder →A distinct 100 W row, not just a wattage label
The Finnex HMC-100S is the manufacturer’s 100 W titanium configuration for 20–30 US gallons. Its HMC table lists an eight-inch tube, 0.83 A at a 110 V reference and a 68–92°F control range. The dimensions and capacity band differentiate it from the 50 W HMC-50S (10–20 gallons, six inches) and the 200 W HMC-200S (40–60 gallons, 11.2 inches). Each boundary is meaningful: Finnex’s table leaves a 30–40-gallon interval between the HMC-100S and HMC-200S ranges, rather than documenting one continuous HMC range for every tank size.
The family chart does not explain the room-temperature assumptions, tank cover or circulation behind its suggested capacities. Treat 20–30 gallons as a manufacturer-stated band rather than a guarantee that a heater will reach a chosen temperature in any room. The exact working water volume and heat loss still matter, and this review does not claim a wattage test or observed recovery time.
Controller, sensor and interruption memory
Finnex describes the HMC as an adjustable heater system with an illuminated digital controller, an external temperature display and a remote sensor placed apart from the heating element. Its control interval is 68–92°F. The manufacturer also says an internal memory stores the last temperature and resumes that setting after a power interruption. These descriptions make HMC different from a simple preset heater, but there is no model-specific tolerance or independently verified temperature log in the evidence reviewed. Use an independent thermometer and select a livestock-appropriate temperature separately from the heater’s available range.
The heating element is titanium and is paired with a flame-retardant protective guard. The HMC family copy describes the series for freshwater and marine environments and labels it submersible. The sources do not show an HMC installation manual, immersion-depth mark, mounting instructions or clearance diagram. The product page’s broad language does not answer whether a specific orientation or placement is correct, and the titanium construction is not treated here as an independently certified shatterproof claim.
Exact identity and the Shop variant record
The official family table names the HMC-100S model row. The current Finnex Shop product data separately identify a 100 W option with SKU HMC-100S and a distinct Shopify variant ID; the barcode field is null. The grouped product page also includes 200, 300 and 500 W options, but not the family page’s 50 or 400 W models. The HMC-100S identity is therefore better bridged to a current manufacturer listing than those two family-only sizes, but a variant record does not establish a specific outside retailer’s offer or current stock.
Three current gallery assets are shared with the group and use HMU file names. They do not show an HMC-100S marking, wattage label or model-specific package, so none is presented as this exact product photograph. Full rated voltage range and frequency are also absent; the 0.83 A figure is expressly tied to the table’s 110 V reference, not a complete electrical supply specification.
Why the listing stays outside the finder
Although the 100 W range is useful for documentary comparison, the current matcher cannot enforce the stated 20-gallon minimum. If it considered only the 30-gallon maximum, it could show this heater for an undersized aquarium. It is therefore retained as a reference-only assessment without a finder match or BuyerShortlists purchase page. This limitation is particularly important because the HMC family includes smaller heater rows and a documented gap between the 100 W and 200 W capacity bands.
The separate HMC-50S review and HMC-200S review preserve their own dimensions and size ranges; they should not be treated as interchangeable settings for a 100 W element. Before considering an exact unit, verify the package label, full power rating and HMC-specific setup instructions. This analysis is based on current manufacturer material, not hands-on use.
Key specifications
Key details at a glance
| Rated heater power | 100 W |
|---|---|
| Lowest thermostat setting | 68°F |
| Highest thermostat setting | 92°F |
| Temperature control | Adjustable thermostat |
| Supported water types | freshwater / saltwater |
| Installation route | Fully submerged, in-tank |
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.