[Delphinus]

Just some additional food for thought. When I first had my BTA, the first year, I had no bubble tips on the anemone. The tank was a 50g with 4x40W NO lighting, so roughly 3wpg. Second year of the anemone was the time I upgraded to halides, but kept my NO's so it was .. um ... 2x175 + 4x40 so about 10wpg, and was bubbled up nearly 100% of the time. Year three, I had an issue with the insulation getting brittle on my NO lighting, so I pulled the NO's out of there, and went to just the 2x175W and upped the photoperiod from 6 hours on the halides to a full 12. So a longer halides photoperiod but less wattage overall (I fully meant to go back and reinstall the NO's and go back to a shorter photoperiod on the halides, but things were so happy with the longer bright period that I never ended up doing so). Now, here's where it gets kind of interesting. The anemone(s) suddenly started growing like stink (going from 3"-4" each to about 6"-8" each within a couple months ... [I say "each" because I actually had three at one point, because of splits and that I was not real quick to give away the new specimens]). But, despite the growth, this is where I saw variable "bubbling up." One them never bubbled up. One of them always bubbled up. One of them ... the part that was closest to the light had bubbles but not the bottom part farthest away from the light.

So, go figure. This seems to suggest that lighting is somehow a factor.

But, currently, the one BTA that I've kept for myself is now in my 75g under 2x250W Iwasaki + 2x110W actinic. It doesn't bubble up at all. So, I don't know if there's some kind of magical threshold that needs to be surpassed, or what (this is about, what, just shy of 10wpg) .... But then again, another thing that is different is that I don't have clownfish in this tank, so perhaps that is a factor.

So in conclusion, I haven't the foggiest clue as to why they sometimes do and why they sometimes don't. I used to have a theory, but, I'm not so sure of it any more. The lighting theory seems to be reasonable, the presence of clownfish theory seems to be reasonable, but perhaps neither theory is the complete picture.. perhaps it is somewhere in between.

Pocillapora, just curious, do you have clownfish in your tank with your BTA?