Mother Natures Gift to Growers Orca is an easy-to-use, all-in-one treatment that inoculates root-zones with four strains of endomycorrhizal fungi and 11 strains of highly beneficial bacteria. They form a symbiotic relationship with plants, facilitating a massively increased level of nutrient uptake, warding off pathogens and promoting glowing, radiant plant health. Mother nature has evolved these complex microbial systems over billions of years, and Orca makes it easy to take advantage of their growth-enhancing, yield-boosting biological properties in any system and in any growing medium! By cultivating a complex culture of beneficial microbes, youll even help to prevent issues with root disease, the bane of many a hydroponic gardeners life. We strongly recommend using Ecothrive Neutralise with this product to avoid the chlorine/chloramine in tap water from inhibiting, or even killing, the beneficial microbes. Recommended Additional Purchases Ecothrive Neutralise - an instant tap water conditioner that nullifies the effects of chlorine and chloramine, maximising the impact of beneficial microbe additives. How Orca Works Endomycorrhizae There are two main types of beneficial fungi: endomycorrhizal and ectomycorrhizal.