Reef salt calculator

Work out how much salt mix to use for a fresh batch, or calculate a gradual water replacement when aquarium salinity needs correcting.

Batch volume The amount of new water you are preparing. Target salinity Choose the finished batch salinity.

Salt mix Manufacturer mixing rates vary, so choose the product you will use.

Convert SG and PPT

A quick approximate conversion. Temperature and instrument calibration can affect the reading.

Specific gravity Parts per thousand

Need the tank's actual water capacity first?