Flourite, Eco-Complete, and Aqua Soil are all proven planted aquarium-specific substrates. Soilmaster is not intended for aquariums, but it's also fired clay, and so it works.
As for changing out the substrate, I would just tear the whole tank down with a 10 gallon. If it was a 100 gallon, already heavily planted, maybe not, but a tear down is the easiest way to replace substrate.
As for changing out the substrate, I would just tear the whole tank down with a 10 gallon. If it was a 100 gallon, already heavily planted, maybe not, but a tear down is the easiest way to replace substrate.