I have not used the spectral Vital but I have used Black powder and think it's a good product. Along the same lines I also like Marine Snow. I don't add these products directly to the aquarium, I remove a cup or two of water from my reef tank and add the product to it and then directly feed the target coral with a turkey baster. Typically when you add it to your aquarium most of the filter food goes to your skimmer and filtration.
Joel