Use the following formulas to illustrate the need for each of these ions.
All measurements are in grams per liter of artificial seawater.
Start with 750 ml of distilled water and add components in the order shown, top to bottom. Mix up the seawater you want without the sodium bicarbonate . Keep stirring to a minimum and use a well stoppered glass bottle. Zero Chloride - The most common substitute for chloride is nitrate. This is not perfect, but can be tried.