Skip to main content

Salt Mix Calculator

Calculate salt mix needed for your marine aquarium.

Salt Mix Calculator

Calculate salt mix for your marine aquarium

Formula

Salt = (Volume in Gallons) × (Grams/Gallon) × Salinity Factor

How to Use

  1. 1
    Enter water volumeInput the amount of water you need to mix in gallons or liters.
  2. 2
    Set target salinityChoose your desired salinity or specific gravity (typically 1.025 sg / 35 ppt).
  3. 3
    Get salt amountSee exactly how many cups or grams of salt mix to add.
  4. 4
    Mix and verifyMix thoroughly, aerate, and verify with a refractometer before use.

Frequently Asked Questions

What salinity should a reef tank be?

Most reef tanks should be maintained at 35 ppt (1.025-1.026 specific gravity). Fish-only tanks can be kept slightly lower at 30-33 ppt.

How much salt per gallon of water?

Most salt mixes require about ½ cup per gallon to achieve 35 ppt. Exact amounts vary by brand — always measure with a refractometer.

Can I use table salt for aquariums?

No. Table salt contains anti-caking agents and iodine that can harm marine life. Use only marine aquarium salt mix.

How long should I mix saltwater before using it?

Mix and aerate for at least 24 hours before adding to your tank. This ensures the salt fully dissolves and stabilizes.