Corals acting different

I was wondering if the way my corals have began closing at night normal or indicative of a possible problem...

My corals have almost always stayed partially (~50 percent) opened at night. A few weeks ago I had a ich issue and treated the tank with herbtana.. The corals didnt love the herbtana as they would close down when added each day (its a 10 day treatment) but over a couple hours would open back up. During that treatment period they started closing all the way each night.. Now the treatment has been finished for a week and they still close each night (practically 100 percent closed). They do open during the day with the lights on... Could it be something wrong or is this normal.. As mentioned, its different behavior than before the treatment as why I am concerned...

 

That's what mines do seems normal