Bubbles missing on my BTA

Ok friends...Heres a question for yas..

My BTA has turned into a long tentacle ...it doesnt have the nice round plump bulbs anymore...How do I get them back?..Is he hungry?..Pissed off?...Why he like this?

Likely a a combination of pissed off and hungry. The BTA is in the tank with the nitrate problem you're fighting right? Maybe that massive water change put him off a bit.
But then again....my nitrate level is undetectable at present and I haven't seen bubbles on mine for 2 months now. Tried increasing and restricting feed without result, restricting/changing water flow, and my lighting doesn't seem to be an issue since he/she sellected that spot after it disagreed with the spot I thought was best for it.
Been reading, reading, and reading for possible causes. Even asked on AP and Reef Central...no suitable explanation provided to date.

Will tag along on this thread and I look forward myself to any possible answers.