Moving or just reaching?

[Angela2016]

Is this BTA about to move or just reaching for more light? I have a kessil AP700 set at 90% about 12 inches above the water on a 120g tank. It closes completely up at night.
Water parameters are ammonia 0, nitrite 0, nitrates 5, calcium 466. Haven't checked mag or alk.

 

[Humblefish]

Probably just reaching out its tentacles for more light.