Some signs that the plants are not getting enough water are the brown tips on the plant. These species are very sensitive to boron and fluoride that are usually found in tap water, and you might be able to see that they have too much of the minerals when the leaves begin to droop.
When the Rainbow tree is underwatered, the stems also show wrinkles.
The leaves can become brown, crispy, and start to dry out. When this happens, water as soon as possible.
Another thing about overwatering is that if this happens, then root rot can begin to set in. You need to remove all the damaged roots from the soil, especially if they appear mushy, fragile, and black. To help with these issues, it's important to cut off a larger part of the root.
Overwatering can also leave the leaves looking brown and ready to fall off. This can happen very early, so you should drain the excess water and wait for the soil to dry before watering to help the plant recover.
Throw away the soil from the pot if there are signs of root rot. Clean everything thoroughly and make sure to put in the pebbles so it will help with proper drainage. Discard any excess water at the base of the pot if you notice tan rings or reddish-brown spots on the leaves.