I've got an RBTA, had it for years. It has never split on it's own, even when the tank goes downhill for a while, and other things go down too. It's gotten as large as 18"ish in diameter, and has crashed down to 4", and everywhere inbetween. It has been put into different systems, has bubbled up, has gotten short stubby tentacles, has gotten very long, no bubble tentacles. My guess, is there are different types, the ones that split frequently, and the ones that don't. I have a friend with a couple of them too, and his has split a few times. Mine has never split from stress, and I've tried overfeeding, 90% water changes, different temps, blasting light, nothing. But, I have cut it, and that's the only way to get mine to split!