Saltwater Mix Calculator

Salt quantity from water volume for target salinity.

Desired Volume (gallons)

Target Specific Gravity

Brand Mix Rate Factor

Tab to move between fields

Salt Needed (grams)

1,325

Salt Needed (cups)

4.9

Half-Cup Scoops9.7

Target Salinity (ppt)35

Recommended Mixing Time (hrs)3

Mix Temperature (°F)78

Total Weight (lbs)86.3

Mix Temp C25.56

How to Use This Calculator

Enter Desired Volume (gallons), Target Specific Gravity, and Brand Mix Rate Factor.
Review Salt Needed (grams) and Salt Needed (cups).
Use Half-Cup Scoops and Target Salinity (ppt) to inform your decision.

How the result changes with Target Specific Gravity

Desired Volume (gallons): Volume of saltwater you want to mix in US gallons.
Target Specific Gravity: Target specific gravity. 1.023-1.025 for fish only, 1.025-1.026 for reef.
Brand Mix Rate Factor: Adjustment for salt brand density. 1.0 = standard (Instant Ocean). Adjust if your brand mixes lighter or heavier.

Salt Needed (grams): Total grams of marine salt mix to add.
Salt Needed (cups): Approximate cups of salt mix (~272g per cup).
Half-Cup Scoops: Number of standard half-cup scoops.
Target Salinity (ppt): Salinity in parts per thousand at your target specific gravity.
Recommended Mixing Time (hrs): How long to circulate and heat before use. Salt must be fully dissolved and aerated.
Mix Temperature (°F): Target water temperature during mixing.
Total Weight (lbs): Combined weight of water and salt for container planning.

Identify Input Parameters
Desired Volume (gallons) = 10, Target Specific Gravity = 1.025, Brand Mix Rate Factor = 1 = 3 input(s) provided
Calculate Salt Needed
Salt Needed = adjustedGramsPerGallon * desiredVolume
1325 = 1325
Calculate Salt Needed
Salt Needed = totalGrams / gramsPerCup
4.9 = 4.9
Calculate Half-Cup Scoops
Half-Cup Scoops = totalCups * 2
9.7 = 9.7
Calculate Target Salinity
Target Salinity = (targetSg - 1.0) * 1400
35 = 35