Grotek The Final Flush is a fertilizer rinse solution that acts to dissolve excess fertilizer salts that may accumulate over time as a result of regular fertilizer applications. Use to remove salts in hydroponic systems, growing media and potting soils. Available in regular and in these scents: Pina colada, blueberry, strawberry, grapefruit and green apple. The Final Flush eliminates excess fertilizer salts in the final stages of growth, and can also be used to correct overfeeding or for desalinization of reusable growing media.