Aquarium Salt Calculator
Calculate aquarium salt doses for treatment or marine salinity.
How it works
Aquarium salt (freshwater treatment): a common dose is 1-3 g per litre depending on severity. Marine mixing: add reef salt to reach 1.020-1.025 specific gravity (≈ 33-35 ppt), about 35 g per litre, measured with a refractometer.
Advertisement
Formula & Method
Aquarium salt (freshwater treatment): a common dose is 1-3 g per litre depending on severity. Marine mixing: add reef salt to reach 1.020-1.025 specific gravity (≈ 33-35 ppt), about 35 g per litre, measured with a refractometer.
Example Calculation
To dose a 60 L hospital tank at 2 g/L: 60 × 2 = 120 g of aquarium salt, dissolved before adding.
Frequently Asked Questions
What salinity should a reef tank be?
1.025-1.026 specific gravity, or 35 ppt, held as steady as possible. Fish-only marine systems can run slightly lower at 1.020-1.025. Stability matters more to invertebrates than the exact figure.
Do I top up evaporation with fresh or salt water?
Fresh water only, ideally RO. Evaporation removes water and leaves the salt behind, so topping up with saltwater raises salinity steadily over weeks.
Is aquarium salt the same as marine salt?
No. Aquarium salt is sodium chloride used as a short-term freshwater treatment. Marine salt is a full mix of the major and trace elements seawater contains. They are not interchangeable in either direction.
Can I add salt to a freshwater planted tank?
It is generally a bad idea. Most aquatic plants respond poorly, and several popular fish - corydoras, loaches and many tetras - are salt-sensitive. Use it only as a targeted treatment in a hospital tank.