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What exact size band does Finnex list for the STE-400?
Finnex’s official STE data row gives the STE-400 a 400 W rating and a 80–100 US-gallon band. The 100-gallon maximum is a capacity screen, not a temperature-performance promise; the 80-gallon floor is not enforceable by this site's current maximum-only matcher, so the STE-400 remains a reference rather than a finder result.
Explore this need in the finder →Can the STE-400 be set to a chosen temperature?
Finnex lists the STE series at 68–92°F, says adjustments move by one degree and advertises ±1°F accuracy. Those are manufacturer settings/tolerance statements, not independent measurements. Check actual water with a separate aquarium thermometer; the STE-400 is not a substitute for animal-specific temperature guidance.
Explore this need in the finder →What must be verified before using the STE-400?
Finnex describes STE heaters for freshwater and marine aquariums and describes remote sensing, titanium and a non-resumable fuse. The sources reviewed do not state this exact STE-400's complete voltage/frequency or immersion depth, orientation and dry-operation rules; a retailer photograph is not an installation manual. Confirm the nameplate and supplied directions before installation. Finnex's 'virtually unbreakable' material language is not treated here as a verified shatterproof-body rating.
Explore this need in the finder →STE-400 identity and published capacity
This review assesses the Finnex STE-400 from manufacturer material; it does not claim hands-on ownership, temperature measurements, or a product test. The US Shop selector names a distinct 400 W option with SKU STE-400 and a separate UPC and variant identifier. Finnex's own specification graphic gives that row 3.33 A, an adjustable 68–92°F control range, and an 80–100 US-gallon aquarium band. The Shop product page presents the STE as a digital controller plus heater assembly, rather than as a bare tube that needs a separately selected controller.
That 80-gallon minimum is not a minor qualifier. The current finder can screen a documented maximum, but it cannot enforce a product's lower rated-volume endpoint. If the STE-400 were included as a buying match for a smaller aquarium, the result could contradict Finnex's own band. It therefore remains reference-only at all volumes, including inside its published band. Its larger 100-gallon ceiling is useful for comparison, not a guarantee of heating in every room or aquascape.
What differs from the neighboring STE sizes
The STE-400 sits between the 200 W STE-200 (40–60 gallons) and 600 W STE-600 (120–150 gallons). Finnex assigns the 400 W version an 80–100-gallon range and lists 3.33 A. Those are the model-specific values; the 200 W model's 1.67 A and 60-gallon ceiling do not transfer to it, and neither do the 600 W model's current or 150-gallon endpoint. The STE-800 reaches 265 gallons but has a 190-gallon floor, making it a different scale of setup entirely.
All four models share the series-level digital control arrangement and 68–92°F span, according to Finnex. The maker says settings change in one-degree increments and advertises ±1°F accuracy. That is a published controller claim, not a measured result from this site. It also does not promise that aquarium water will equal a selected value in a tank with different ambient conditions, circulation, evaporation or cover. A separate thermometer remains the way to verify water rather than relying on the LED display alone.
Materials and protections in the source record
Finnex identifies the heating tube as titanium and its comparison chart lists a nickel heating coil, push-button digital control, Japanese components, and an ETL listing to UL standards. The product description calls the titanium corrosion-resistant and advertises freshwater and marine use. It also describes a remote temperature sensor in the aquarium and a redundancy-protection design. The series chart marks out-of-water protection as a non-resumable fuse. These are manufacturer statements, not independent durability or failure-rate evidence. A non-resumable fuse can require replacing the unit after a fault; it should not be treated as a way to safely operate the heater without water.
The exact STE-400 retailer photo in the library shows a carton labelled “STE-400” and “400 WATTS” beside the guarded element and controller. That is a model-identification image, not a performance photograph. The current official selector separately identifies this wattage, while the exact carton marking makes the retailer image distinguishable from a family image reused for all four options. The image by itself says nothing about current stock or voltage compatibility.
Important gaps before installation
Finnex's model graphic provides an amperage value but does not state the voltage basis or frequency beside the STE-400 row. Check the exact device label and instructions before selecting a circuit. Do not infer the complete electrical supply from the product's US Shop location or from a retail description. The manufacturer documents a remote sensor and depicts the system at an aquarium, but the current official instructions index reviewed here does not list a STE manual. The sources in this assessment do not establish a minimum immersion line, a permitted mounting orientation, a clearance requirement, or dry-operation permission.
That uncertainty matters because the STE-400 is a higher-output unit than the 200 W size, not because it is automatically more dangerous or more suitable. A source-based assessment cannot fill in operating details from a sibling model or from a photo. Verify exact packaging and the supplied directions; do not treat a heater guard, titanium tube or redundancy feature as a substitute for correct water level and setup.
Where the STE-400 fits in a comparison
A keeper with a tank in Finnex's 80–100-gallon band may want to compare the STE-400's adjustable digital display, remote-sensing arrangement, titanium construction and listed protections against a glass thermostat heater. The meaningful question is whether those documented features and the exact 400 W capacity row suit the keeper's installation and power supply. If a smaller tank is involved, the 80-gallon lower bound makes this the wrong model to choose from an “up to 100 gallons” headline.
The site excludes this model from recommendation because the numeric rule cannot represent the 80-gallon floor and the reviewed manufacturer sources do not establish the full installation plan. That decision preserves the distinct SKU, UPC, 400 W, 3.33 A and capacity information without offering a misleading finder recommendation. A separate STE-400 model-reference lookup is available on this page; it does not verify a seller's package or installation fit, and it does not change the 80-gallon lower limit. Read the heater-sizing guide for the significance of two-sided capacity ranges, then use the finder for other configurations whose supported plan can be checked under the same conditions. A rated band remains a starting reference, not proof that a target water temperature will be reached.
Key specifications
Key details at a glance
| Rated heater power | 400 W |
|---|---|
| Lowest thermostat setting | 68°F |
| Highest thermostat setting | 92°F |
| Temperature control | Adjustable thermostat |
| Supported water types | freshwater / saltwater |
Use the exact model’s instructions for operating limits, supplied equipment and version differences.
Sources for this review
Sources for this assessment
- Finnex Shop — STE Series selector, 200/400/600/800 W
- Finnex Shop — STE Series variant data
- Finnex Shop — STE series model specification graphic
- Finnex — Titanium heater series comparison chart
- Finnex — Instructions index checked for STE documentation
- SaltwaterAquarium.com exact-model STE listing photograph — STE-400
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.