K2SO4 is exactly what it says it is. That's the chemical formula for Potassium Sulfate. You dose it for the potassium it contains which plants use. Usually you get enough potassium from dosing KNO3 and K2PO4. However, if your fish produce enough nitrates that you don't need to dose KNO3 or if your plants are showing signs of potassium deficiency then some people dose additional K2SO4 to provide it.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.