What Temperature Should My Reef Tank Be?
Quick Answer
The ideal temperature for most reef tanks is 76-80°F (24-27°C), with 77-78°F being the sweet spot for corals and fish.
The ideal temperature for most reef tanks is 76-80°F (24-27°C), with 77-78°F being the sweet spot that works well for the vast majority of corals, fish, and invertebrates.
Why Temperature Matters
Temperature directly affects the metabolism of every creature in your tank. Coral's symbiotic zooxanthellae (the algae that give corals their color and energy) are particularly sensitive to temperature changes. Even small swings can trigger bleaching or stress responses.
Temperature Guidelines by Livestock
- SPS Corals: 76-79°F (prefer stable, slightly cooler)
- LPS Corals: 76-80°F (slightly more tolerant)
- Soft Corals: 75-80°F (most forgiving)
- Fish: 75-80°F (species dependent)
- Invertebrates: 75-78°F (cleaner shrimp and snails prefer cooler)
Stability Is More Important Than Exact Numbers
A stable 79°F is far better than a tank that swings between 76-80°F throughout the day. Aim to keep daily fluctuations under 2°F. Larger swings stress livestock and can trigger coral bleaching or disease outbreaks.
Equipment for Temperature Control
- Heaters: Use quality heaters sized for your tank (3-5 watts per gallon). Consider using two smaller heaters for redundancy.
- Controllers: Temperature controllers provide failsafe protection against heater malfunctions.
- Chillers: Essential in warm climates or rooms that heat up. LED lights produce less heat than older lighting, reducing chiller needs.
- Fans: Evaporative cooling with fans can drop temperatures 2-4°F but increases evaporation significantly.
Monitoring Your Temperature
Don't rely solely on your heater's thermostat—they can drift over time. Use a separate digital thermometer to verify accuracy. Track your temperature over time with the ReefBay app to spot trends and catch equipment failures before they become problems.
What to Do About Temperature Swings
If your temperature is fluctuating:
- Check heater placement (should be near flow)
- Verify heater wattage is adequate
- Consider room temperature fluctuations
- Add a controller for automatic regulation
- In summer, consider a chiller or cooling fans
A consistent temperature between 77-78°F gives your reef the best chance to thrive while leaving room for minor seasonal variations.
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