Alright, just keep them in light brackish for now. When you decide to raise the salinity to the higher spectrum, then do it fast to save yourself money (assuming you're doing 50% pwc weekly). You will eventually need to get your GSP in marine water asap once you spend money for a protein skimmer, refugium, and live rocks (all should cost ~$1000 and will keep pwc to once a month).
Good luck.