August:   Thank you for contacting the University of Vermont Extension Master Gardener Helpline with your questions about your Rainbow Eucalyptus tree.  Below are a couple of growing tips:

This tree requires moist conditions to thrive.  The tree must be well watered.  However, make sure the soil is not too soggy with standing water.  It is recommended that if the plant is indoors in a pot, watering with distilled water is best.

Containers should be large enough for the tree to grow.   You indicated that you will be transferring the tree to a larger planter.  However, you may want to consider replanting sooner in a larger pot with good drainage.   The tree grows very fast, so check the roots to make sure they are not growing in circles (girdling) around their current pot.  If you see girdling roots, transplant the tree to a larger pot soon.

The tree requires warmth, and the temperature should not drop below 50 degrees.  Recommended temperatures are 70 degrees to 85 degrees.  It is too late now to check the temperature of the glass walled stairway on extremely cold nights, but perhaps this may have happened, so keep this in mind for next year.

Another interesting fact about this tree is that it is common for young trees to drop and regrow many leaves.   Also, common is for entire branches to drop and then grow new branches nearby.

Preventing, Diagnosing, and Correcting Common Houseplant Problems (psu.edu)

https://letsgrowflorida.com/pages/rainbow-eucalyptus-tree-instructions-care-1

I hope you find this information helpful.