Originally Posted by tsunami
Rotala macrandra var Narrow Leaf will grow in pretty much the same conditions as Rotala macrandra, Rotala wallichii, et al. Give them moderate NO3 (5-10ppm), high PO4 (1.5-2ppm), plenty of light, and plenty of iron (Flourish/TMG). They also seem to like water on the softer side (doesn't have to be SOFT, but not the more extreme GH 12-15+).
If Rotala magenta really does not work out, a more suitable replacement would be Ludwigia arcuata (as they have similar leaf texture and color) which is much easier to grow.
My experience has been to the contrary as far as low GH goes. Until recently I had no luck growing Rotala macrandra or Rotala magenta. The new growth tips always stunt and the small new leaves are twisted. Even though my tap GH=8, I thought I might try more Ca just in case because the symptoms do look like calcium deficiency. Well, after a month of CaCl2 addition (GH to 13), my rotala macrandra is drop dead gorgeous, blood red, growing/branching like crazy. Rotala magenta is doing much better as well.