Finnex THH-300S 300 W Titanium Heater Tube

Exact-model photograph is not verified. No exact THH-300S unit or package photograph is verified. The existing ordinary review uses a shared official THH-family appearance image showing an unmarked guarded tube and cord box; it does not identify the selected wattage or package. This reference lookup is text-only and does not close the separate exact-photo status.

Finnex's THH table identifies this 300 W tube for 40–80 US gallons, with a 10.63-inch tube and a separately listed 58-inch controller-to-heater lead. Finnex also requires a separate temperature controller and water above 150 ppm TDS; the reviewed source set does not establish a complete input rating, exact controller match or installation route. Treat this as an exact-model reference lookup, not a ready-to-use fit recommendation.

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

• Finnex's separate THH-300S table row lists 300 W, 2.7 A at 115 V, a 40–80 US-gallon water-volume band, a 10.63-inch tube, a six-inch field labelled Power Cord and a distinct 58-inch controller-to-heater cord.
• The model code is THH-300S; Finnex's graphic presents it as a distinct THH row, not the TH-300S or THD-300S 300 W configurations.
• Finnex says the THH tube requires an external temperature-control unit and must not be plugged directly into a wall outlet. Its family overview describes an out-of-water cutoff and an LED status box; that cutoff is not temperature control.
• Finnex names freshwater and marine use but separately requires water with a TDS reading above 150 ppm. The threshold remains a condition rather than an inferred feature of every freshwater or saltwater tank.
• Finnex places the out-of-water sensor where the heating element meets the cord, says to keep that portion higher than the rest of the heater, and calls for cleaning and functional checks every 30 days.

Limits to weigh

• The 40-gallon lower endpoint is material. The current finder can express an upper-volume limit but cannot enforce this floor, so the THH-300S remains outside ordinary matched recommendations even when its maximum appears suitable.
• The 2.7 A figure is explicitly referenced to 115 V; the reviewed manufacturer sources do not provide the exact model's full input-voltage range or frequency. Do not treat 115 V as a complete nameplate specification.
• A separate temperature controller is required, but the reviewed Finnex sources do not identify the exact compatible controller, its control range or a complete controller/tube package. This tube must not be treated as a stand-alone heater or connected directly to mains power.
• The strict TDS condition is not represented in the public questionnaire. The broad freshwater/marine statement alone does not establish that a particular tank's water meets the manufacturer's above-150-ppm requirement.
• The inspected Finnex instructions index contains no THH entry; that omission does not prove a manual does not exist. Exact immersion depth, orientation, mounting, heater clearance and a complete installation procedure remain unverified in this source set.
• The table's six-inch Power Cord entry is unusual and separate from its 58-inch controller-to-heater lead. No total wall-to-heater routing length is inferred; verify both measurements on the exact item.
• The reviewed material does not establish a particular seller's current offer, exact shipped package or package contents. The THH family photograph is not a model- or wattage-marked THH-300S unit.

Check before ordering

• Check the item and carton for the exact Finnex THH-300S / 300 W identity; do not accept the TH-300S, THD-300S or another THH wattage as the same configuration.
• Compare the actual aquarium volume with Finnex's complete 40–80 US-gallon band. The band is a maker sizing guide, not a heating guarantee; account for the tank's room temperature, heat loss and target rather than relying on wattage alone.
• Measure the aquarium water's TDS and confirm it is above 150 ppm before relying on the manufacturer's THH guidance. Freshwater or marine labels do not replace this check.
• Confirm which separate controller is compatible, that its load rating suits this tube, and exactly what the seller's package includes. Never connect the THH tube directly to a wall outlet.
• Read the specific unit's electrical nameplate for its complete voltage and frequency before connection; the table's 2.7 A at 115 V is not a substitute.
• Obtain and follow THH-specific instructions for immersion, orientation, mounting and clearances before use. The guard and out-of-water sensor do not supply missing installation directions or authorize dry operation.
• Follow Finnex's stated sensor care: keep the cord-end sensor portion higher than the rest of the heater, clean and check it every 30 days, and stop using the heater if the sensor is not functioning.
• Verify the table's six-inch Power Cord field and separate 58-inch controller-to-heater lead against the actual unit and intended cable route; do not infer a total cable reach from either number alone.