Discoma will grow under any condition and can survive anything. Although, if they are unhappy, they will release themselves and float around. they will hit a comfortable stage and multiply like crazy.
Rhodactis can be hardy, like med flow- med light to high light, but they will not explode quite like discomas
ricordea- I am assuming you are talking about florida and not yumas? florida, need good light, not too high current, but they tend to do well for a year, then shrink. can be hardy, but will melt if rubbed with sand. Yumas are the hardier of the two, but only if you get past that initial melt down stage.