Orca is a myco/bacterial supplement, like their powdered product Great White. There are better products out there, but it will work if you already got it. Actually, the same company makes a super concentrated new version called King Crab (bacteria only). All you need is to buy the sample, which is about $5 plus another 5 for shipping. Compare those CFU in those products, and you'll see the King Crab is vastly more concentrated. An alternative to it is to brew a tea with worm castings, but that $10 sample will last you for an entire grow or even two, it's quite concentrated. I really like Dynomyco if you want a mycorrhizae only product.