Oh the joy of keeping R. macrandra. I have had this plant turn several different colors in a matter of weeks for reasons that I can't explain. It started out bright red, then turned a lighter pink color, then back to bright red and after a heavy trim it went kind of a peach/orange color and the leaves almost looked variegated. It's one of those plants that puzzles me. It can grown like a weed and then if you look at it wrong it will start to wither away. I do believe after several attempts to keep this plant happy that it does best in lower kH water. Also after talking to some others I think it may help if its planted densely together. I will continue to try to figure out what makes this plant tick and what it likes and doesn't like.
What is your kH?