Planted Tank Enthusiast
Join Date: Mar 2013
Location: Baltimore, Maryland
Need more info on your tank. Lighting and tank size, specifically. Also, what your co2 is like. Also, what species of rotala?
For rotala rotundifolia, to keep it red, I think you'd need fairly high light and plenty of co2. Iron is an important supplement but is not the solution to keeping plants red.
Also, most green rotala species with the capability of being red usually only become red at the tops, where the light is the strongest. Don't expect this entire plant to be red.