Well, that is a good question. I have treated mags before and a single course was sufficient. In this particular case, I have done two and the anemone is still doing the inflate/deflate cycle - looks good in the morning but flattens out in the late-afternoon. At this point I am not sure why another round would be useful (something about fools and expecting different results from the same actions .....), plus I am off for business for a week, so no opportunity to try a third round. I was thinking of putting it into one of my inhabited QT tanks, but think I will leave it in the HT because if it does die it may take down the QT without me home to intervene.