tongue coral help.

[meetpierre]

I have a tongue coral that i've had for 1 year. When i got the coral it was about 4" and now it's 9+" long. It's a great piece and i hate to lose it.
Monday of this week my tongue coral started to close up. I don't now what is going on. I did a water change on Saturday and all looked good Here is the water peramaters.

CA =500, PH 8.2, Slin= 1.024 and No=0 and alk=2.5 kdh water temp 79
lighting 2-250 watt MH on for 10 hrs water flow is medium to high

I've been tring to raise the ALK up and I noticed that when adding my ALK buffer the tongue coral seems to close up. but after a day or two it will open again. I'm dosing with seachem ALK buffer (dry)

The rest of my LPS and SPS are doing Great.

Can someone give me some advice on helping my long time freind out. I just don't know what to due.