Potassium sulfate (K2SO4), also known as sulfate of potash, arcanite, or potash of sulfur, is a white crystalline salt which is soluble in water. This chemical compound is commonly used in fertilizers, providing both potassium and sulfur. In Spirulina cultivation, K2SO4 is used in the famous Zarrouk formula which was used by NASA in the 1960s, as well as many other culturing formulas, providing spirulina with these essential micronutrients.
Where to Get Potassium Sulfate
K2SO4 can be difficult to find in shops, and will usually be mixed with a bunch of other minerals which aren’t necessarily needed for spirulina cultivation. So, to make things easier, here are a few suppliers that sell (almost) pure potassium sulfate in crystalline form on Amazon.
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