Care
Mar 1, 2026
What is the ideal salinity range for a reef tank?
Quick Answer
Most reef tanks do best at a stable salinity around 1.025 specific gravity (about 35 ppt). Stability is more important than tiny adjustments.
The ideal target for reef aquariums is typically 1.025 specific gravity (about 35 ppt). Keep salinity consistent day to day to reduce stress on fish and coral.
Recommended range
- Target: 1.025 SG
- Acceptable: roughly 1.024-1.026 SG
- Avoid fast swings greater than 0.001 SG
How to keep salinity stable
- Use an ATO to replace evaporation with fresh RO/DI water
- Calibrate your refractometer regularly
- Mix saltwater thoroughly before water changes
If salinity drifts, correct it slowly over 24-48 hours. Log readings in the ReefBay app so trends are visible before they become problems.
Helpful Calculator
If your refractometer reads low or high, use the Salt Mix Calculator to estimate how much saltwater adjustment you need.
Next Step CTA
Open the Salt Mix Calculator, then log your correction in the app at /app/calc-salt-mix.
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