bubble coral acting strange.

[DEAD_BY_DAWN]

so i have had this bubble coral for three months now ,and half of it has acted strange,it will inflate in deflate itself quite a few times during the day,expel its zoonanthelia about three times per week ( there is no loss of colour), feed once a week,waters great cal-450ppm,alk 12dkh,sal1.026,nitrate under 5ppms,ph8.1,lighting is on my user info any ideas is this normal ,in the end it does look healthy.so why only half of the coral is acting odd ?

[Mak]

Sounds normal to me...well considering there behaviour. Mine's about 12"+ and hosts a couple of percs .

[MCC]

mine sometimes does tat too

i realiezed.....hermit crabs irritates it...so it shrinks or as u say deflate

so maybe u have some critters tat like to pick at the bubbles when it is inflated