Salt dose calculator
How much salt it takes to bring a pond to the concentration you are aiming for, allowing for whatever is already in there.
Pond volume
Both gallons are listed separately because they are not the same measure. Not sure of your volume? Work it out first .
Concentration
Enter the level you are aiming for. Leave the second box blank if you are starting from fresh water.
Fill in the pond and the target
Both are needed before there is anything to weigh out.
Always check the level with a proper test
Use a salinity meter or a salt test kit, and go by what it reads — not by this figure. These numbers are a loose guide only. They assume your volume is right and that the pond starts exactly where you said it does, and a real pond rarely obliges on either count.
Salt does not evaporate. It stays put as water leaves, so topping a pond up does not dilute what is already dissolved, and dosing again after a top-up stacks on top of it. What level to aim for is a judgement about your fish and your situation — this works out the weight, it does not advise the target.