Is the tank fully cycled, as rams will not survive with any traces of ammonia or nitrIte and nitrAtes needs to be as low as possible, preferably below 20ppm, a slightly softer, more acidic water is also preferred but many are tank bred these days and can be happy enough in harder water. Mine were in hard water, ph 7.8 and thrived. German blue rams are the more sensitive of the rams (I dont know about ballon rams but as said they are not naturally occuring rams), Bolivian rams are the hardier of the bunch. In a 35g tank providing you dont have too many other fish, two would ok, but no more, they like plenty of hiding places, rocks to spawn on and lots of plants (real or fake).
You will need to keep a good water changing routine going, to keep the nitrAtes low and because they do best with 2x weekly water changes.