How to judge health of SPS corals

[Stones]

Depending on the type of coral, they can become totally bleached within a week. My personal experience is that acros are much less suseptible to bleaching than are encrusting montiporas. Try moving the coral to lower levels in the tank or move to an area with greater but still dispersed flow. Hope this helps.

Polyp extension and colour are both excellent signs that sps are doing well in your tank.