How to Estimate Your Pond Volume Using Salt

You can determine your pond’s volume by adding a known amount of salt and measuring how much the salinity increases. Because 1 pound of salt added to 100 gallons raises salinity by about 0.12% (1.2 ppt), this relationship lets the calculator determine your total water volume.

1. Measure your starting salinity

Test your pond’s salinity and write down the reading.

2. Add a known amount of salt

Use the Pond Salt Dosage Calculator to estimate how much salt to add based on your best guess of the pond’s size.

Aiming for a salinity increase of around 0.2% (2 ppt) works well for this test.

For accuracy, temporarily turn off your autofill so no fresh water enters the pond during the process.

3. Allow the salt to fully circulate

Once the salt has dissolved, wait about 3 hours for it to mix evenly throughout the pond.

4. Measure salinity again

Test the salinity a second time.

Subtract your original reading from this new reading — this difference is your salinity increase, and it’s what you’ll enter into the calculator along with the amount of salt you added.

5. Enter your numbers into the calculator

The calculator will use your salt amount and salinity change to estimate your pond’s true volume.

Note
0.1% salinity = 1 ppt (part per thousand)