Salt Mix Calculator
Enter the water volume (in gallons) and select your salt mix from the list. Enter the current salinity level (PPT) as well as your desired salinity level to find out how much salt mix will be required to reach the desired salinity. The salinity of fresh RO/DI water will measure 0 PPT and 35 PPT is the target salinity level for reef aquariums.
New batch starts at 0 salinity
Calculated results are ONLY estimates, minor adjustments may be required. There will be slight variances based on the moisture content of the salt mix and the temperature of the water will affect salinity measurements.
The water should be heated to 75-78°F and always use a refractometer to measure salinity. Add salt mix slowly, in small increments, to the full volume of water you’re trying to mix then adjust as needed to reach your target salinity. Weighing dry salt mix with a scale is the most accurate method of measurement.
Salt Mix Calculator
Mixing your own saltwater is a routine part of reef keeping — but getting the ratio right is essential. Whether you’re preparing water for a new tank or a regular water change, this calculator helps you measure the proper amount of salt mix based on your preferred brand and target salinity.
Why Use This Calculator?
Each salt mix brand has a unique formulation with specific calcium, alkalinity, magnesium, and trace element levels. This tool helps you:
- Mix the correct amount of salt per gallon or liter of RODI water
- Match your desired salinity level (typically 1.024–1.026)
- Avoid over- or under-mixing
- Compare usage efficiency between salt brands
Start Slow: Recommended Usage
Note: These values are general starting points based on manufacturer guidelines. Always test salinity using a calibrated refractometer or digital salinity probe after mixing.
Environmental factors like humidity, storage conditions, and water temperature can affect your final salinity, so be sure to mix thoroughly, allow the solution to stabilize, and adjust as needed before use.
Supported Salt Mixes
- Tropic Marin Pro Reef
A balanced salt mix designed for modern reef tanks, offering stable calcium, magnesium, and alkalinity levels. - Tropic Marin Classic
A traditional blend ideal for fish-only systems or mixed reefs, with slightly elevated buffering capacity. - Tropic Marin SYN-Biotic
Enriched with probiotic bacteria and organic additives to support biological filtration and coral health. - Tropic Marin Bio-Actif
Contains bioactive compounds that promote microbial stability, coloration, and coral vitality. - Red Sea Coral Pro
High-alkalinity formula (11–12 dKH), formulated for fast-growing SPS corals and nutrient-rich reef systems. - Red Sea Salt
Balanced for mixed reef environments, with moderate alkalinity (~8 dKH) and consistent trace elements. - Instant Ocean Sea Salt
A widely trusted choice for fish-only systems and beginner reef tanks, offering reliable parameters and good solubility. - Reef Crystals Reef Salt
Enhanced with additional calcium, magnesium, and vitamins for demanding reef systems and coral growth.
Tips for Best Results
- Always use RODI water to prevent introducing unwanted nutrients
- Mix in a clean container using a powerhead or heater to help dissolve the salt evenly
- Test salinity after mixing, not just by volume — small errors compound over time
- Aerate your saltwater for 4–6 hours before use, especially for large water changes
- Keep salt dry and sealed to prevent clumping or chemical imbalance
