Red cabomba likely would do better with higher light than its green cousin which explains the denser growth at higher regions of the tank. It looks like its straining to reach the light. another sign is the lower leaves either withering or dropping off making the plant look very stemmy. what is yoru dosing regiment? how much FE is added?
ओं मणिपद्मे हूं
My life extends far beyond the limitations of me
Keeper of the LIST