I use soil based tanks, and they are nearly a self contained ecosystem.
no ferts, no co2, no filter, and a water change every six months or so (if that).
JonnyD, was that supposed to be a pun?
got to the ROOT of the problem with your amazon swords? It was a lack of ferts at the roots, right? :P
Rotala changes colors to a deep green, and then a dep reddish purple in high light, but it just doesn't like any of my low tech tanks. (haven't tried it in soil yet, might do that...)
Do you dose with flourish?
If not, that's your problem. If you dose already, I have no idea.
(Rotala is a fast grower, so has slightly higher nutrient demands than java fern. The rotala isn't getting what it wants, but the java fern is getting plenty- ya know?