A lot of people seem to use cheato macroalgea. All it needs to grow is lighting. Most people say 5 watts for every gallon of fuge but it will thrive with less. Most people leave there lights on 24/7 in the fuge, or run the opposite light cycle that the main tank it on. IMO I would get some live rock and live sand from a friends pre established tank, or your own tank if its been set up for a while. You can also but the both of them, but it might take a little longer to seed.