Mykos by Xtreme Gardening is available via EBay and will do the same/similar thing. Have used it for ages. Don't know if it really does anything, but always add it "just in case". Can not hurt, so why not? I really should try an experiment to find a definitive answer for myself. A side by side grow with clones maybe?
If I do, will share it with GD.
Cheers,....... Organoman.