Hum...You could try using something like this as a more permanent flat swing.

Or you could try making a bead flooring (similar to this) out of safe beads

Or lastly, maybe you can replace the sea grass mat each time Tetra goes through it (that way she's always got her beak busy!). You can fine sea grass mats on ebay for around 3 USD or perhaps at a local craft store?

If you want help looking online for any of these or similar let me know - I LOVE looking for bird toys online. :>