Finnex HMC-100S 100 W Titanium Aquarium Heater

Exact-model photograph is not verified. This reference route is text-only in the current renderer. The full model review uses the official HMC-series component image with a family-only caption: it shows the controller, guarded heater element and remote sensor, but does not identify HMC-100S, its wattage, element length or package. No HMC-100S-specific photo is verified.

Finnex identifies HMC-100S as a 100 W configuration with an 8-inch tube and a 20–30 US-gallon manufacturer-stated band. The separate official Shop option data names SKU HMC-100S. This is an identity reference, not a fit recommendation; the finder cannot enforce the lower 20-gallon boundary.

Search results may include other models. Confirm the exact model, applicable region, condition and included parts before ordering.

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Documented model details

• The HMC family table names HMC-100S at 100 W, for a suggested 20–30 US gallons, with an 8-inch tube, 0.83 A under the table’s 110 V reference, and a 68–92°F control range.
• The lower capacity boundary matters: the adjacent HMC-50S row is 10–20 gallons, and HMC-200S is 40–60 gallons. Finnex does not document a continuous HMC row for 30–40 gallons; a model should not be selected by treating its maximum as the only capacity condition.
• Finnex describes an illuminated external digital controller with adjustment and remote temperature display, a sensor separated from the heating element, and memory that resumes the saved setting after power interruption. These are manufacturer descriptions, not independent accuracy or stability measurements.
• The family material describes a titanium heating element, a protective flame-retardant guard, freshwater and marine use, and a submersible heater. Those broad family claims do not supply a size-specific installation procedure or prove the package of a particular seller offer.
• The grouped Shop option record separately identifies the 100 W choice as SKU HMC-100S and variant 51471028388139; the barcode field is empty. Its visible options do not include the family table’s HMC-50S or HMC-400S configurations.
• The family table’s 0.83 A value is tied to its 110 V current column; it is not a complete voltage or frequency rating for the unit.
• Finnex’s official HMC family-component image shows the controller, guarded heater element and remote sensor, but no exact model marking, wattage, element length or package. It is mapped to the HMC family with an explicit family-only caption in the full review; it does not identify the 100 W assembly.

Limits to weigh

• The documented 20–30 US-gallon range is a manufacturer suggestion, not a guarantee for a particular room temperature, target or aquarium heat loss. More importantly, the existing finder cannot enforce the 20-gallon minimum, so this model remains outside active matches and purchase recommendations.
• Full rated voltage and frequency remain unknown; the table’s current figure is referenced to 110 V. Check the actual unit nameplate rather than infer an electrical rating from wattage or the U.S.-oriented listing.
• The instructions index I inspected has no HMC entry, but that does not establish that an HMC manual is unavailable. Specific immersion depth, waterline, mounting and sensor-placement directions remain unverified; directions from HMH, HMS or another family are not transferred.
• The exact Shop variant has no UPC/barcode in its saved record. The model identity is supported by the manufacturer family row and Shop variant, but that does not establish a current third-party seller offer, exact delivered package or availability.
• An exact Amazon U.S. product listing was not verified. The saved search response was unavailable before listing details appeared, which is not evidence that the product is absent. A buying destination must be labelled as a model search unless an exact listing is independently established.
• No HMC-100S-specific package or wattage photograph is verified. The full review uses the official HMC-family component visual with a caption that leaves the exact size and length unidentified; this reference route is text-only, and the shared HMU-labelled Shop images are not substituted for this specific variant.

Check before ordering

• Confirm that the physical heater and documentation identify HMC-100S, 100 W and the HMC family; do not substitute HMC-50S, HMC-200S or another wattage based on a grouped-page image.
• Compare the actual aquarium volume and heat-loss needs with Finnex’s stated 20–30 US-gallon range. Do not treat 30 gallons as a stand-alone maximum-only match or rely on this reference for tanks below 20 gallons.
• Read the actual unit’s voltage and frequency label before connecting it. The 0.83 A table value is specifically stated at a 110 V reference and does not establish the complete supply range.
• Request HMC-specific instructions and verify immersion, waterline, placement, clearance and sensor positioning for the exact unit; do not borrow directions from another Finnex family.
• Confirm the seller package includes the exact heater configuration and the controller, sensor and guard described for the HMC family; the grouped variant record and generic image do not prove a third-party package.
• Treat any unverified retailer route as an exact-brand/model search, not a confirmed HMC-100S listing. Check the item title, model marking and package before purchase; no sibling model is an acceptable identity substitute.