I've tried superthrive, but after prolonged use I noticed mutated growths on my plants. I feel like its either a mutant clone, or something to do with conditions.
A friend of mine gave me her Cattleya skinneri after having "had trouble" growing it (and she grows spectacular orchids!!!). I cleaned off all of the crappy stuff and potted it in plain old-fashioned bark and charcoal, and its growing roots like crazy. I'm trying the same approach with this plant!
KelpMax actually works on my Vanda seedlings. There are probably also kelp products available at nearby hydroponics shops.
Kelp has components that have a measurable, quantifiable effect on plant health and performance, something that Superthrive does not. Find me an independent control study that proves the efficacy of Superthrive.