The salt is made in 1 tonne batches and laboratory tested before it leaves to make sure it is within the specfication on the bucket, we also retain a sample of every batch. This way we can go back and retest the levels in the laboratory if needed.

There are several things that could lead to a low test result on a fresh saltwater mix.

Salinity

The levels on the salt are given at a salinity of 35ppt (1.0264 S.G) at 25⁰C. If the salinity of the saltwater is below this there will be less mineral content and the readings will be slightly lower.

We recomend that an accurate, callibrated, seawater refractometer is used when checking your mix. There are a lot of brine or saltwater refractometers sold for the aquarium market, in most cases these are inaccurate on seawater and should not be used.

If you use a Hydrometer which is calibrated at 25⁰C then you must have the water at 25⁰C to get an accurate reading, check the calibration temperature printed on the hydrometer. If the water is colder or warmer than 25⁰C then you will need to use a conversion chart to get the actual reading at 25⁰C.

Test kit innacuracy

It is always important to use accurate test kits. Test kits that have been open for a while can read incorrectly and care must be taken to use the kit as instructed without contaminating any of the reagents.

Test kits should ideally be checked against a reference sample to confirm they are reading correctly. In some cases it is best to repeat the test three or four times and then avaerage out the readings.

Precipitation

When mixing the saltwater precipitation of minerals can occur. Please see the FAQ in the link below on more information.

Precipitation within new saltwater mix.

Salt has not finished mixing fully

It is possible to get inacurate test results if the Seawater has not finished mixing fully. Even after the water has cleared it can take time or the elements to reach their natural equilibrium.