This is what always happens to my C. Muscosa. I'm not really sure how to get that thing to grow roots and keep them there. Am I watering too much, not enough? Is the soil supposed to retain more water? Less water? I would just take. Those pieces with green at the top and bury them up to the first set of undessicated leaves in a well-draining mix and let it reroot. Just don't let it get soggy. I like to use a spray bottle to root succulents.

It is best to take off as much of old soil as possible - leaving it defeats the purpose of using different mix - at least to some extent. It is recommended to add 'generous amount of perlite, 50% or more' - I think you did well :) You could grow succulents in pure perlite, or pure pumice, or pure grit (or some other inorganics) - they all provide good drainage and aeration. Some bags of perlite have lots of dusty fines, so it may be good idea to sift it. I use a kitchen sieve to do that, putting all sifted perlite into a container with warm water (most likely it doesn't have to be warm, just the way I do it) and rinse it. Then I strain water using same sieve and use it. If I was to use the mix you mentioned, I would sift it too; most often there is still lots of fines in the mix. You should check if there is list of ingredients on the bag to see what it contain. Too much of organic ingredients may attract bugs like fungus gnats since they like wet organics. Not saying you shouldn't use it thou :) Many ppl. use this mix, just have to be careful about watering (that's why addition of perlite-to make drainage better). Personally, I don't buy it since I don't really see any benefit using it for succulents.

Hi, Thank you everyone very much! To answer your questions: - Location: Melbourne, Australia - Sun: this area gets a good half a day of direct sunlight - Water/Drainage: This photo as I mentioned, was taken immediately after it rained, so it looks very wet. It is generally well protected from the rain by the leaves. Yes the rocks and sand and coal (i think perlite is another name) is ⅔ of the pot from the bottom. There are 4 big holes in the bottom of the pot and it drains really well. The plants were growing like crazy in this pot for over a year. And I replanted them 3-4 month ago, adding those rocks and sand. So the drainage issue is unlikely. The roots looked healthy. I could put some more rocks on top to protect it from the rain even more. -Plant type: don't know the name, it certainly looks just like K. luciae pictured above in Crenda's comment. There is a different succulent on the side. The very tall fast growing one. The leaves start to develop these black spots or dried edges and then bubble almost in an acid burn looking manner and die off. Should I trim those effected leaves?

Leaves that start yellowing and are soft are most often water logged. The most important would be to give it good drainage - pot with drainage holes and very well draining mix. Mounding up the soil is not problem - it actually helps to direct excess water away, but in water retaining mix it helps just a little. Big pot + water-retaining mix = very big chance of rotting. After these are corrected, the plant will need lots of light.