[Hydraa]

I tried a test of your question and the atomsophere did not convert to none on a gas giant. I did however look at the data files and there are data set up for ring worlds and sphereworlds to be gas giant/none. Just no planets are.

Perhaps MM should put a warning in for a atomsphere converter on a gas giant that is trying to convert it to none.

I did not know so I tested to see if the plants converted to the atomsphere of the race on the planet and it did. I had a oxy race conquered a hydrogen race and put them on a methane planet and converted the atomsphere. It converted it to Hydrogen, not oxygen.

I don't know what it would convert into if you had mixed races on the planet