I am concerned about my Desert Rose plant. Some of the leaves are turning yellow and some are turning brown. The plant has been growing and has new growth. The Caudex was always hard as a rock but now it's a little softer. I use a Moisture Meter to measure the wetness and it reads green. I repotted this plant in late June and I am afraid to pull it out of the soil to check the roots. Is there anything else I can do? Please see the Photo's

It appears to be over potted/over watered. They need to be treated like cactus. Very course/fast draining potting mix, and full sun. They like to be crowded in the pot.

Thank you for your response. Should I be repotting this now or waiting for the end of summer.
The existing pot is 9" what size do you think I should use.
Thank's again for your response.