There is good FAQ here on BER, causes, and suggested treatments. Just click on FAQ link at the top of the page and scroll down to Blossom end rot. In this case, I agree strongly with the others your container is much too small and your plant is likely rootbound and exceptionally stressed. It will be quite difficult to prevent BER in this case. Try removing a sucker from it, rooting it in a glass of water and then planting it in a much larger container. There are several posts here on how to root suckers. Good luck. Dave

ML, For Aloes, it's easy. Healthy Aloe roots are yellow (the shading depends on the species of the Aloe and the age of the root). It is a natural process for older, thinner roots to die off, so when you repot go ahead and clean up the root ball. The old ones look dead and peel off pretty easily.

Ooops...guess I should have checked my spelling. I meant to spell "monstrose" Montrose is a rock band from the 70's! Did some Googling.... I stand corrected on the difference between crested and monstrose. Learned something new today. I've always just lumped them together. See the link below. When I originally saw the subject to this post I pictured an E.Obesa that had become very large....Monstrous. Here is a link that might be useful: Monstrose vs. crested

I think the critical factor is soil choice and watering habits. Ideally, you'd be growing in a medium that makes over-watering something you'd actually need to work at for it to become a problem. I build my soils so they hold little to no perched water, and can't remember the last time one of the fungaluglies was a player in the death of a plant. This is the ugly planting I referred to that was put together from what was available when a visiting bonsai 'artist' conducted a workshop. It's in the 5:1:1 mix topped with dead moss and there are no drain holes in the pot at all. I used R/O water for irrigating and fertilized with fish emulsion and STEM. I think we did the workshop in Aug and the plants were tiny things in little 1.5" pots - little larger than a cell pack cell, so the growth of the plant, such as it is, was from August to sometime in spring. You can see the closed buds on the hornbeam I'm layering the top off of next to it. Below you can see I pruned the mess hard I let it grow until the next spring Then cut it back again You can see the stub from the first chop. I summered it outdoors & did some pinching I'd neglected to do before to make it full, and pawned it off on the first garden visitor that could find promise in it. The bottom leaves are original on the plant, so about 3 years old, and they look pretty good for all the low light and other adversities they suffered. Like I say - it's never been a tough plant to keep happy. I've repotted several of them for others - did one very large one with a 2.5 - 3" trunk during a repotting demo for a garden club, and cut those back to reveal a decent structure too, and they all did just fine. Al