Why won't my xenia open up

[salisbury a d]

Last week I bought a rock with some xenia on it.
They were open the first two days but have not opened since.
My book says they need direct light and strong current.
I have them placed about 6 inches from the top of the tank and in a moderate current and they still haven't opened.
pH 8.2
ammonia 0
nitrite 0
nitrate 0
What is wrong?
My lights are three 55 watt PC.
Two 10,000 k white
One actinic
Adam

 

[clamps]

is there any fish that might pick at it to keep it in, i had a blue devil damsel that picked at mine till it was allmost dead she is in a QT now and the xenia is comming back ,my LFS said she shouldent have done that, but she did.and with reg.feedings i know she wasent hungry??anyhow just what i saw in mine, it would try to come out and she would hammer it back in ..........i guess what im sayin is watch your fish real close

 

[reefur.]

check your salinity. IT is what makes them "PUMP". 1.024 is about as low as you can go.....

 

[banshee]

I found out that mine were not opening up, too. I placed them in a spot with less current and now they are fine.

 

[bosco0633]

mine are doing awsome at the top of my tank under direct current created from my aqua clear 300. They are close to the light source. My buddy NERDY has the best xenia's ever and he adds iodine like a religion. Good luck

 

[nerdy]

I add Iodine every other day and they have grown huge and multiplied like wildfire!!!!

 

[salisbury a d]

It has been a while since I have added iodine. Could that be it?
My salinity is 1.022.
I have raised the salinity to around 1.024.
Adam

 

[salisbury a d]

Good news!
My dad said they were open earlier today but he noticed that a hermit crab climbed on the rock and disturbed them so they closed.
Adam

 

[nerdy]

I think that would be it. They rely heavily on iodine to flourish.
Here is what mine look like

 

[salisbury a d]

Looks great.
Thanks for the input.
Adam

 

[bang guy]

Originally posted by Nerdy
I think that would be it. They rely heavily on iodine to flourish.
Here is what mine look like
Do you know of any scientific evidence that they use Iodine? I've looked and looked and I can't find any.
These are mine with no I2 supplement:

 

[nm reef]

I've often heard that Iodine is reported to help...but I've also heard that regular addition of Iodine is not needed and in fact can accumulate in our systems eventually reaching toxic levels.
I have no hard scientific data for any of the assorted opinions on Iodine...but about a year ago I added a single stalk of xenia. Since it has grown to a very large colony that has been fragged several times. I never add Iodine but I do try to change about 5 gal of my water about once a month. Mine seem to prefer higher levels of light(they literally climbed to the top of my reef to be directly below 4x65 10k PC's&2x110 super actinic VHO's)...plus the seem to prefer a moderate current.I have also noted that they respond poorly to fluctuations in PH levels...they actually are one of my living PH early warning systems...

 

[nm reef]

Here is another pic showing most of the colony from about 4 months ago...