Elite 91 ROOTS is one of the most highly effective and dynamic root enhancing products available on the market today! This unique, proprietary liquid formulation contains the highest quality ingredients, boasting high concentrations of multiple, diverse and viable beneficial bacteria, fungi, vitamins, plant derived minerals, protein hydrolysates, polysaccharides, organic chelates & activators as well as natural boosting health and growth hormones all in one bottle for optimal root development and increased plant vigor. Plant Growth Promoting Rhizobacteria (PGPR) are a group of diverse free-living bacteria that colonize and construct a protective biofilm around the rhizosphere (root zone) and significantly benefit the root growth and vigor in plants. Â Â Â A Little Goes A Long Way! 250 ML Bottle @ ~ 0.5 ML per gallon will treat 1,892 Liters (500 gallons US) of nutrient solution. 1 ML per gallon will treat 946 Liters (250 gallons US) of nutrient solution. 500 ML Bottle @ ~ 0.5 ML per gallon will treat 3,785 Liters (1,000 gallons US) of nutrient solution. 1 ML per gallon will treat 1,892 Liters (500 gallons US) of nutrient solution. 1000 ML Bottle @ ~ 0.5 ML per gallon will treat 7,570 Liters (2,000 gallons US) of nutrient solution. 1 ML per gallon will treat 3,785 Liters (1,000 gallons US) of nutrient solution.