In the past week, I have noticed that one of my hermit crabs has been sitting at the top of my tank, just sitting there. I have been checking him often and today I came home and he is no longer moving (I took him out the tank to make sure). There had not really been any cause for it. The only things I have done recently are start to dose alkalinity and a very small amount of calcium (trying to get my alk up from 6.3). I have not dosed any more than .1 dkh at a time, .2 per day and usually dose 0.05 dkh 4 times a day. Yesterday, I removed my carbon because I thought it might not be helping my cyano issue. No corals in the tank, only snails, hermits, and fish which seem to be doing well. Coralline has been growing a lot more recently.