Bio-Gold (HFBG500) Bio-Gold Supplement (0.4-2.5) Bio-Gold is a storehouse of rhizospheric micro-organisms that colonize the rootzone creating an unparalleled environment for healthy plant growth. Hydroponic Applications: Mix 0.6 grams per 1 gallon of dechlorinated water in reservoir and run through system. Bio- Gold can be used weekly with nutrient change. Using more Bio-Gold than what is recommended may actually reduce its effectiveness. Do not use hydrogen peroxide with Bio-Gold. Manufacturer's Product Information 2009 MSRP $ 101.95