I stopped using Superthrive when I realized the plants grow fine without whatever it is in the ingredients.

Here's a couple of articles giving a little insight into Superthrive and additives in general.

The first link is specifically from a Bonsai site, but if you substitute "cannabis" every time you see "bonsai"...it still applies. Excellent info for even an advanced gardener, in an easy to understand article. A tad long, but the importance of the info is tremendous.

Second article is more from the horticulturist quoted in the first link, whom I've often quoted in these forums when attempting to de-bunk gardening myths.

Debunking the Myths of Bonsai | Knowledge of Bonsai

Superthrive Myth