The sea salt you can use can be regular, inexpensive sea salt, such as Mediterranean Sea Salt, either course or fine crystals. It is evaporated sea water and little processed retaining trace minerals. These minerals and other possible substances in sea salt help to stabilize and give Activated EM (bokashi spray) a much longer shelf-life.
Note. Do not use regular salt, i.e., table salt, which is mined and processed to remove the minerals.