Mills Nutrients Ultimate PKMills Nutrients Ultimate PK Get a BIG finish with Mills Ultimate PK a tried & tested Phosphite stimulant. It ripens fruit, bulks your bloom & hardens plants in the last 2 4 weeks of flowering. It also improves root health it makes a great root cleaner and increases oxygen flow to roots. Use it to get a bigger bloom with a stronger taste & aroma. Increases size & weight Hardens cell structure Enhances root health Improves taste & aroma Cleans rootzone