My open open brain coral still hasn't fully opened up. My nitrates are down to 1 ppm. I have replaced my light bulbs and even added more light. So why
hasn't my open brain coral responded by opening? It still mostly stays tightly closed up. I remembered that over the summer I raised the tank temperature so that the fluctuating temperature of the house would would have less of an impact on water temperature. Come to think of it, my open brain coral was closed most of the summer. Perhaps it didn't like the elevated temperature. Maybe all it wants is lower temperature water. So, on Saturday, I lowered the temperature from 79 to 77 degrees F. The next day the coral opened up more than I have seen in months. See the picture below.
However, by evening it was deflated again. It's deflated every night when I come home from work. The picture below is how it looks every night and the way it has looked since summer.
The picture below is how it used to look. I took this picture back in January 2008. Unfortunately, I wasn't logging my tank conditions back then so I don't know what my temperature was.
I'll probably lower my temperature a little more this weekend to observe the results. Everything else seems fine with the temperature at 77 deg F.
