Effective supply of organic carbon, plants use light and carbon dioxide to synthesize organic carbon, an essential energy source, called photosynthesis. The three major fertilizers in plants are potassium and nitrogen phosphate. But organic carbon is essential for plants to absorb it. It most effectively supplies organic carbon to plants. Bad algae occur when there is too much fertilizer in the water. When used, plants absorb enough fertilizer in the water to prevent bad algae as a result.