SPS retracting polyps at night - should I be concerned?

[djryan2000]

So I've kept a bunch of SPS frags for almost a couple months.**In the day they all have full polyp extension and seem to be very healthy.**However, once the lights go out, within 15 minutes, they all completely retract either the entirety or a large portion of their polyps and many of them look bone white.**Once the lights are on, they all extend again within 15 minutes.** All the corals do seem to be thriving - they're colored up well and seem to be growing.

I've looked for any signs of pests and couldn't find any. All new corals have been dipped in Coral RX.

My original hypothesis was it was related to my bottomed-out phosphates.**I started dosing potassium phosphate daily and it sits at .1ppm.**I purchased a Bird of Paradise from my LFS since, and the poylps stayed out for a couple nights and then tonight are retracted.


Sent from my iPhone using Tapatalk

 

[Oldreeferman]

Perfectly normal most corals retract at night except night feeders and low light non photo synthetic ones.
The time to start worrying is if they retract during the day...................