I have a Plexaurella sp. gorgonian that I have had for 13 years. It grows like a weed for me and I have to trim it regularly every month or two. Recently I added an automatic water changing system to my tank. I have a 180 gal tank and it changes about 2 gallons /day. I also recently changed out some carbon that I had not changed in a while. I checked my alkalinity and it was at 4 dKh last night. I bumped it to about 5.5 dKh and I will bump it some more tonight to get it to about 8 dkh. I'm not sure if the gorgonian is not opening due to possible light shock from the new carbon, the low alkalinity, or the new water change regime. None of my other corals including LPS, SPS, leathers are affected and all seem perfectly happy. Any thoughts or suggestions?