Kalanchoe leaves turning black
My kalanchoe (idk the type) that I've had since December was doing great a few days ago. I started bringing it outside during the day, once it got warm enough outside, to get some extra sun, and it didn't seem to mind. The stems grew, the leaves got bigger, and it got more green. Then a couple days ago it was a little yellow in some spots. The next day, browning. I checked for bugs, don't see any. I brought it inside to see if that was the issue and now it looks like this. Black splots on the smaller leaves and on the underside of others. The big leaves look in bad condition. The white spots are my hard water leaving calcium on the leaves, so it's not powdery mildew. Are there secret bugs in not seeing? I'm going to cut off the blackened leaves but how do I prevent this from happening again? I think I over watered? What's wrong here.