Aquarium heater size calculator
Compare Aqueon’s heater table with Fluval T Series limits. Enter your tank’s water volume and temperatures. The starting values are an example, not a temperature recommendation.
For the example: 100 W on Aqueon’s chart. Both makers’ charts ↓
What the heater charts say
Aqueon’s setup table assumes a 68–72°F room. For an intermediate volume or temperature rise, this tool chooses the next larger published row or column, and says which it used. It does not extrapolate into colder rooms. Aqueon’s separate Pro PDF differs at the 10-gallon / 15°F and 75-gallon / 15°F entries; for those two we show no wattage.
| US gal row | 5°F rise | 10°F rise | 15°F rise |
|---|---|---|---|
| 5 | 50 W | 50 W | 50 W |
| 10 | 50 W | 50 W | 50 W |
| 20 | 50 W | 100 W | 100 W |
| 30 | 100 W | 100 W | 150 W |
| 55 | 150 W | 150 W | 200 W |
| 75 | 200 W | 200 W | 300 W |
| 100 | 300 W | 300 W | 300 W |
| 120–125 | 2 × 200 W | 2 × 200 W | 2 × 200 W |
| 150–210 | 2 × 300 W | 2 × 300 W | 2 × 300 W |
Fluval’s T Series manual specifies a rise below 10°F and lists conditions that can require more heat, including an uncovered tank, cooling sources and room fluctuations. The tool uses that stricter manual boundary even though the FAQ says “more than 10°F.” Fluval’s gallon and liter limits are rounded differently; both must fit, whichever unit you enter.
Before you buy the heater
- Check the chosen heater’s control range, submersion marks, allowed orientation and available water depth.
- Use a separate thermometer and check actual water temperature under the coolest room conditions.
- Two heaters in an Aqueon table row means the stated quantity and wattage. Splitting the watts between two heaters of another model doesn’t on its own give you a backup or protect against overheating.
- For a room or tank beyond a chart’s bounds, obtain an exact model recommendation from the maker. Do not substitute a universal watts-per-gallon rule.
Compare heaters or keep the fit and temperature checks in your equipment plan.