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What tank band does Finnex state for HMC-300S?
The HMC-300S row is 300 W, 60–80 US gallons, 2.50 A at the table’s 110 V reference, and 12.4 inches long. The 60-gallon lower endpoint cannot be enforced by the current quiz matcher.
Explore this need in the finder →What temperature range does this HMC configuration share?
The HMC table prints 68–92°F for the 300 W row. Finnex describes an adjustable digital controller and remote sensor, but gives no tolerance or independent stability measurement.
Explore this need in the finder →Can the HMC-300S go in an external filter?
The source labels the HMC a submersible heater; it does not document an inline external-filter route. The reviewed instructions index has no HMC manual, so do not place it into plumbing or assume a specific mounting method.
Explore this need in the finder →The middle 300 W HMC configuration
The HMC-300S is individually named in Finnex’s family table as a 300 W model for 60–80 US gallons. Its listed tube length is 12.4 inches, amperage is 2.50 A at the table’s 110 V reference, and the printed control interval is 68–92°F. At 60 gallons this row meets the HMC-200S band; at 80 it meets the HMC-400S band. The table does not explain whether every range endpoint assumes a standard room, covered aquarium or a particular temperature rise, so those meeting points should be read as chart boundaries, not proof of identical performance.
The specified tube is longer than the HMC-200S’s 11.2 inches and shorter than the HMC-400S’s 15.1 inches. That physical difference is relevant to tank layout, but full dimensions for controller, sensor, guard and attachment are not given. Check the actual unit and manual for space and mounting requirements.
Control features and what they do not establish
Finnex presents HMC as an adjustable digital system with an illuminated display outside the tank and a remote sensor separated from the heating source. The maker says the sensor separation avoids local heat interference and that memory restores the last set temperature after power returns. These are manufacturer descriptions, not a measured accuracy or reliability claim. The 68–92°F range indicates what the controller can be set to, not what temperature is appropriate for an animal or what temperature the aquarium will maintain.
The titanium heater element is paired with a flame-retardant protective guard. Finnex’s HMC text includes freshwater and marine suitability language and describes the family as submersible. But the pages inspected do not provide the full HMC installation sequence, minimum/maximum waterline, allowed orientation, dry-operation instruction or external-filter authorization. The current manual index lists other heater families, not HMC; it would be unsafe to transfer their diagrams or instructions to the HMC-300S.
Exact model evidence
The HMC-300S has a corresponding 300 W option in the current grouped Finnex Shop product record. Its SKU is HMC-300S and the variant has a distinct Shopify ID; no UPC/barcode is supplied. The family page contains the capacity and length row, while the Shop record confirms the exact size option. The listing’s shared imagery does not identify a 300 W heater and uses HMU-prefixed image filenames. It is not an exact HMC-300S photo, so no substitute is shown.
As with the other models, the published current field is amperage at 110 V, not a complete input-voltage range and frequency. Verify the label on any exact retail package. A grouped product page and a family table do not prove the item is in stock or that a third-party listing contains the same configuration.
Why the 60-gallon floor keeps it out of matching
The existing finder can compare a requested volume with a manufacturer’s stated maximum, but it cannot enforce the HMC-300S 60-gallon minimum. Returning it for a smaller aquarium would violate the source’s published band. This review therefore remains a reference, not a quiz match or ordinary questionnaire-based purchase recommendation. Its separate model-reference lookup supports identification and seller checks only; it is not tank-fit approval. No simplified fit rule is used to hide the missing boundary.
For adjacent documentation, see the individual HMC-200S and HMC-400S reviews. The 60- and 80-gallon overlaps are not evidence that one size can replace the other in a particular tank. Consider actual water volume and environmental heat loss, verify a suitable animal-specific target, and confirm the exact installation and electrical instructions before use. This is a source-based review; no hands-on test is claimed.
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 |
| 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.