I recently purchased 3 succulents, gorgeous little thing. They are my first. But one has brownish tips on the end of it that it didn't have before. I have a south facing window and they get about 2 hours of direct light and about 8 more indirect light. Its leaves aren't mushy so I'm thinking its not over watering. Any ideas? I will add pics of what it looks like. My first photo is just what all of them look like.