Best? Who knows. But I know that it's very good, and very effective for growing out fish fast. BH has a proven itself over time, to be very effective, and relatively cheap. I like it. Downside it can be, and usually is messy. Have to keep up on your WC's, but if you're growing out fish, you have to change water frequently no matter what is fed. I've never known the "guru" who you mention breeding himself, but more of a middleman/broker...Bill