Sorry, please stay on topic.
I'm looking at some of the numbers when breeding lightning and lava. It looks like its a weighted average of visitors x lvl x number of times bred.
Lightning and Lava based on visitors = a rainbow?
I hear it has to be all level 10 dragons and its a just a random chance as long as they are level 10.
If anyone knows how to get an Air dragon without saving the gems for one let me know.