Comparison
Compare the Fluval E Series electronic heaters
Fluval's E Series is a family of electronic aquarium heaters, not one model with interchangeable wattage labels. The reviewed English-language Fluval USA product and archive pages identify E50/A771, E100/A772, E200/A773 and E300/A774, each with its own item number, capacity and power. Other official US routes omit E50; that omission does not establish that the model is retired. This comparison covers these four individually identified E configurations, not every Fluval heater.
Fluval USA E Series configurations
| Model | Item / UPC | Power | Aquarium rating | Manufacturer dimensions (L × W × H) |
|---|---|---|---|---|
| E50 | A771 / 015561107716 | 50 W | Up to 15 US gal / 60 L* | 2 × 1.125 × 9.75 in |
| E100 | A772 / 015561107723 | 100 W | Up to 30 US gal / 120 L | 2 × 1.25 × 11.75 in |
| E200 | A773 / 015561107730 | 200 W | Up to 65 US gal / 250 L | 2 × 1.25 × 14 in |
| E300 | A774 / 015561107747 | 300 W | Up to 100 US gal / 375 L | 2 × 1.25 × 14 in |
The first two dimension axes are short sides of the listed envelope; the long mounting axes are 9.75 inches on E50, 11.75 inches on E100 and 14 inches on both E200 and E300. The North American manual includes A771 and Fluval's official E-family comparison lists the 120 V / 60 Hz version. Check item number, UPC, wattage and plug/electrical rating—not only the “E Series” name—when comparing a retailer offer. *Fluval's E50 product page is inconsistent about metric capacity: its title and other E-family sources pair 15 US gallons with 60 L, but its specification table prints 50 L beside the same 15-US-gallon maximum. This guide uses the consistent US-gallon value for the finder and preserves the discrepancy for buyer verification.
Shared controls, shared cautions
Fluval describes E50, E100, E200 and E300 with a digital water-temperature reading, dual sensors, VueTech color alerts, an adjustable setting and an integrated protective guard. Its stated E-Series range is 68–93°F, with 0.5°C / 1°F steps. The screen is a helpful cue: green is the stated near-setting band, blue indicates a low reading, red a high reading, and larger deviations flash. A separate low-flow message warns that circulation around the heater may be inadequate. These are not independent tests of whole-tank temperature, and the source does not provide a numerical display-accuracy tolerance.
The protective case does not make the E Series shatterproof. Fluval's manual identifies the heater core as glass and says the guard must remain installed. It requires water above the marked MIN line and no more than 100 cm / 39 inches of immersion. It also recommends strong circulation, often near a pump or filter outlet, and permits either vertical or horizontal placement. The instructions call for a 20-minute in-water acclimation before powering on and a 30-minute cool-down before removal after unplugging. Use the exact instructions for the unit in hand.
Do not treat the capacity as guaranteed performance
The listed aquarium maximum helps exclude a model when the working volume is too large, but it is not a guarantee that a selected target will be maintained. Fluval's E Series FAQ says that a room-to-setting difference over 10°F / 6°C can call for additional heating capacity. The manual also notes room conditions, tank cover and circulation among factors that affect heating. Tank volume, coldest normal room temperature, target and water movement are useful considerations together; watts alone do not describe a measured performance curve.
Fluval's English-language US product page identifies E50 item A771 and UPC 015561107716, and an official US heater archive also lists it. Two other Fluval US routes omit E50. The positive model-specific listing supports treating E50 as a current-reference configuration without claiming availability or stock; the differing official routes remain a source limitation, not evidence that one wattage or generation replaces another.
Individual assessments and scope
Read the separate E50/A771 assessment, E100/A772 assessment, E200/A773 assessment and E300/A774 assessment. The individual model pages and family/manual evidence support the table above. These are source-based assessments; no hands-on test, measured aquarium outcome, current price, stock status or independent sensor-accuracy result is claimed. Exact model photos are mapped for E100, E200 and E300; an exact E50 photo is not verified, and no sibling image is used as a substitute.
Sources: Fluval's current English Fluval USA E50 page, first page of the English Fluval USA heater archive, older /us E Series comparison route, E100 page, E200 page, E300 page, the E-Series FAQ and the A771–A774 North American manual.
Saltwater, a 15-gallon limit and adjustable control together
For a same-condition electronic comparison, see classic EHEIM e e50/e300 and WLAN thermocontrol+ e 150 W Type 3666, 200 W Type 3667, 250 W Type 3668 and 300 W Type 3669. Their capacity maxima differ, and matching at a lower volume does not establish lower-range suitability.
The conventional AquaTop GH-75W also appears in the 15-gallon marine adjustable result; it remains inside its own maker-listed maximum at 16 gallons. Compare the conventional GH-150W and GH-300W assessments with GH-75W: these are not the quartz-glass GH PRO versions. The five HTG guarded-glass sizes are also marine-listed adjustable in-tank models: at 15/16 gallons, HTG-100/200/300/400 pass the conservative maxima, while HTG-50's 13-gallon ceiling excludes it; at 39/40 gallons HTG-200/300/400 remain, with HTG-200 at its conservative 40-gallon endpoint. The 200/300/400 W current exact pages state higher ceilings than the old official table, so the result uses 40/60/100 pending a current-version bridge. See the separate HTG-100, HTG-200, HTG-300 and HTG-400 reviews.
The requirements must coexist in one exact plan. At 15 US gallons, the saltwater-adjustable finder returns 57 candidates; at 16, 52 remain after GH PRO 50 W, EHEIM Jäger 50 W, thermocontrol e50, Fluval E50 and Fluval M50 cross their separate ceilings. At 39 gallons, 41 candidates remain, and at 40 there are 38: Jäger 100 W, thermocontrol e100 and HeatUp 150 leave their distinct maximum screens. Type 3667 reaches its 106-gallon limit but not 107; Type 3668 reaches 159 but not 160. At 159 there are seven saltwater-adjustable candidates; at 160 there are four. The current-linked Jäger 300 W manual uses a conservative 260-gallon cap, while classic e300 and thermocontrol+ e300 are separately rated to 264. At 264, three candidates remain—the two EHEIM e300 configurations and AquaTop TH-C800; at 265 only TH-C800 remains active. The matcher does not apply approximate lower tank ranges, so a large-heater result at a small volume is not a sizing recommendation. P is preset, not adjustable, and the T models remain out of the marine set while their evidence conflicts.
Decision: At 15 gallons, 57 saltwater-adjustable candidates remain, including distinct GH PRO and HTG sizes, HeatUp models and the listed Fluval/EHEIM lines. The 16-gallon result has 52 candidates: GH PRO 50 W, Jäger 50 W, thermocontrol e50, Fluval E50 and M50 have left their own 15-gallon ceilings. See the 15-gallon matches or the same conditions at 16 gallons. Compare the full OASE comparison with the exact GH PRO 50 W and WLAN Type 3666 / 150 W, 3667 / 200 W, 3668 / 250 W and 3669 / 300 W. These models' approximate lower volume bands are not additional matcher rules; a maximum-only result is not a heat-output guarantee.
Decision: The saltwater-adjustable finder returns 52 candidates at 16 gallons. GH PRO 50 W, Jäger 50 W, thermocontrol e50, Fluval E50 and M50 are excluded above their separate 15-gallon maxima; other sizes retain their own limits. See the 16-gallon result. Compare separate GH PRO 100 W and 200 W configurations with HeatUp 100 and the OASE size guide rather than inferring model facts from wattage.
Decision: At 39 gallons, 41 saltwater-adjustable candidates remain; at 40, there are 38 because Jäger 100 W, thermocontrol e100 and HeatUp 150 cross their separate upper limits. The conventional GH, distinct GH PRO, HTG and EX models retain their own capacities. See the 39-gallon set or the 40-gallon boundary. Compare the OASE capacity limits and individual GH PRO 200 W/300 W assessments; a larger model appearing in the result does not prove it is well-sized for a smaller aquarium.
Decision: At 106 gallons, 12 saltwater-adjustable candidates remain, including Type 3667 / thermocontrol+ e 200; at 107 it, classic e200 and Jäger 200 W leave their separate 106-gallon ceilings, leaving nine. See 106 gallons or the 107-gallon result. Compare Type 3667 with Type 3668 and Type 3669.
Decision: At 159 gallons, seven saltwater-adjustable candidates remain, including Type 3668 / thermocontrol+ e 250; at 160 there are four after the classic Jäger/e250 and thermocontrol e250/Type 3668 pass their ceilings. At 264, three candidates remain: classic e300, Type 3669 and AquaTop TH-C800; at 265, only TH-C800 remains active. See 159 gallons, 160, 264 or 265. Compare Type 3668, 3669, classic e300 / Type 3639 and TH-C800. The one remaining match is a scoped library result, not a market-wide claim.
No reviewed saltwater-adjustable operating plan covers 265 gallons, one gallon above both independently documented EHEIM e300 maximums; this scoped result is not a claim about every heater on the market.