It's SUPER concentrated. 1ml to 30ml of feed. A normal person shouldn't use it up within less than 2 years. I originally bought it to help combat root rot, which it did, along with regular rez changes and a reduction in temperature. I haven't had root issues in a long time, but whether I can attribute it directly to this product, not so sure. I've been using it lately in brewing a beneficial micro-organism tea, along with hydromyco, subculture-B, and earthworm castings. Still haven't seen any sign of root troubles.
I also use it in my cloner, but I can't even say it honestly helps them root any faster.