Rhipsalis need to be moist all the time. Haworthia can't stand that much water. And both need more air circulation than that terrarium can provide. Get those plants out of that terrarium into a pot or pots. And water more frequently. Oh keep the Haworthia away from the Rhipsalis.

Rob are you sure Rhipsalis need to be moist- I have found the opposite. My R. coke bottle is in a clay pot with cactus mix. Maybe some Rhipsalis need to be moist, but the coke bottle type want to be a bit drier.

From rhipsalis.net"

Watering

How often Rhipsalis cacti should be watered depends on various factors, like for example the size of the plant in relation to the pot, the temperature and the substrate.

From spring to autumn they can be waterd copiously. Give as much water as the earth can take. Any excess that leaks into the saucer has to be removed after a few minutes. Stagnant water can lead to rotting of the roots. Allow to dry before watering next.

If water is needed can be gauged by the weight of the pot, a wet soil is heavier than dry.