Wow. With so many passionate posts here you'd think aquariumplants.com was claiming to be selling a bucket full of cancer curing drugs rather than aquarium substrate.
Acrillite-based substrates (hey, if it looks like a duck, and quacks like a duck...
) work well so it's not even a bad substrate that they're selling.
I wouldn't be surprised if they drop the product from their site and return to the simpler life of fielding complaints from angry plant buying customers.