Join Date: Oct 2008
Location: Salt Lake City, UT
When the Rotala reaches the surface, trim it at a lower point to encourage the stems to 'branch,' and create a thick bush. The rule of thumb (very general) is that when you trim a stem, two more shoots appear from the trimmed portion, which makes for thick bushes of stem plants, so the goal is to carefully cultivate it so that the first trimming point is low enough to allow for consequent trimmings that can grow and create more 'branches,' so typically you want to make this cut behind an object like a stone or piece of driftwood so it isn't seen.
You can also replant the tops if you like.
When you trim hairgrass, trim it all the way to the very base of the substrate (it will grow back thicker and allow you to keep it in control), but wait until the hair grass has filled in a bit and carpeted most of the surface area before doing so.
Aquascaper for life.