Which is the last standing depends entirely on the conditions in your tank. Different types of algae have different growing conditions.I don't think a reactor needs an air stone/supply to grow GHA. There would be lots of ways to put things in a reactor for the GHA to hold on to.
I guess I need to know which would be the last algae standing: gha, cheato, or turf/ATS algae. To figure out what would be the best algae for a reactor.
so I build an DIY upflw ATS based of of SM hogs, been running 2 weeks not any growth in it but ere is GHA in the DT tank is going through new tank syndrome.
I did alot of research when building it and not sure why its not doing anything. i do think with some tweaking it would perform great. might be user error.