SPS color changes

[hammondegge]

I have noticed something happening that i had not noticed before. It may be because it has not happened in in the past, or it may be because i had not noticed it.....but,....some of my brighter colored acros, notably a blue and a green, have on occaision shifted colors quite rapidly. on the green acro about half will turn rose colored (not brown), presumably overnight, and it will then color up again in about 24 hrs. this may happen once a week or so. on a blue acro a portion has turned pale purple and returned to the original intense blue only to return to purple again. i am not concerned, the colors are pleasing and the corals are healthy, but i am curious to know if others experience this.

I also have noticed a blue stag frag that will be a solid blue some days and a two tone blue fading to browns the next day. are these growth conditions? i have some of the same corals rapidly encrusting at the base with pale or white colorations.

my guess is that is due to more rapid growth than i was accustomed to seeing. what do you think?

btw this is under fairly new Phoenix 14k bulbs, ~2months old.

[thedude]

Does your alkalinity swing? I've found that definitely changes a coral's colors is seconds.

[hammondegge]

not overall, but i do use kalk in my auto-top off system. i was kinda thinking that it may happen if my system stirs about the same time as topping off. the pattern of coloration changes and position of the corals doesnt seem to indicate this (in relation to my return) however i do have a lot of very eratic current in the tank.

other than this possible short term peak in localized alk...alk stays at 11dkh solid