They are essentially the same thing only two different brands. They both combat algae and cyanobacteria using bacteria cultures that use up all the nutrients. This starves the nuisance algae and cyanobacteria. Eventually you are instructed to use your skimmer which removes the bacteria you added before it over populates. So doing both would be like a double dose of one or the other. You may as well pick one and try it as instructed. If you aren't happy with the results, then try the other brand.
Either way they will come back unless you keep using the product or figure out another way to manage your nutrients. Also, if you have herbivores then you'll have to plan how to feed them once their food is gone so they don't starve.
