HesapHanem

Aquarium Salt Dose Calculator

Enter your water volume and dose per liter to find how much aquarium salt to add.

How it is calculated

The amount of salt is grams = volume × dose, where volume is the water volume in litres and dose is the target concentration in grams per litre. The tablespoon figure is grams ÷ 15, which assumes about 15 g of salt per level tablespoon; real salt packs differently depending on grain size, so weigh the salt when accuracy matters. The tool also labels the dose: below 1 g/L it is called a low dose, from 1 to 2 g/L (inclusive) a general or preventive dose, and above 2 g/L a strong or treatment dose. Volume and dose must both be above zero. Use the actual water volume, not the tank's stated capacity, since gravel, rocks and decorations take up space.

Worked example

A tank holds 75 litres of water and you want a dose of 1.5 g per litre. Salt needed: 75 × 1.5 = 112.5 g. In tablespoons: 112.5 ÷ 15 = 7.5. The tool shows 112.5 g, 7.5 tbsp and labels this as a general / preventive dose, because 1.5 sits between 1 and 2 g/L. Weighing the salt on a kitchen scale is more accurate than counting spoonfuls.

Try this example →

Common mistakes

  • Entering the tank's label size in gallons or the stated capacity instead of the real water volume in litres. A 75 L tank filled to the rim with gravel and decor holds noticeably less water.
  • Typing the dose as a percentage or as grams per gallon. The field is grams per litre, so 1 g/L and not 0.1 or 4.
  • Adding the whole dose at once to a tank with fish in it. The tool gives a total amount only; how and how fast to add it is a separate decision, and some fish and plants tolerate salt poorly.
  • Using iodized table salt or salt with anti-caking additives. The dose assumes plain aquarium salt (sodium chloride) and the weight is of that salt.
  • Treating a tablespoon count as exact. Coarse and fine salt weigh differently per spoon, so rely on grams and use tablespoons only as a rough guide.

Sources

About this calculator

Aquarium salt (sodium chloride, not iodized table salt) is dosed by grams per litre of tank water, used to help treat certain freshwater fish diseases and parasites, ease osmotic stress, and support gill function in some species and situations. Because overdosing can harm salt-sensitive fish and live plants, this calculator converts your target dose per litre and total tank volume into a precise gram (and tablespoon) amount rather than leaving it to guesswork.

It's a routine reference for freshwater aquarium hobbyists treating a quarantine or hospital tank, adding a general tonic dose, or following a specific salt-based treatment protocol from a fish disease guide, where getting the concentration right matters for both effectiveness and the safety of sensitive tankmates.

Was this helpful?

You can pick up to 3 reactions.

Comments (1)

  • Editorial team

    The tool works for top-ups too. Salt stays in the tank when water evaporates, but it leaves with water you remove. After a 20 L water change in a tank dosed at 1 g per L, enter 20 as the volume and 1 as the dose to see the 20 g that the new water needs to match the concentration. Which species do you keep, and what concentration do you stay under?

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators