Who Gives A Fish Forums

Temporary solutions are fine, but don't rely on them long-term. Corals need consistent lighting to avoid stress. Have you noticed any changes in their behavior since the light failed?

If it's out of warranty, you might consider upgrading to a newer model. The Hydra 32 has better reliability and features. How's your tank coping with the lack of light so far?

Sealed units are tricky because they're not meant to be user-serviceable. If it's under warranty, contact AquaIllumination immediately. Otherwise, you might need a replacement. How long have you had the unit?

Marimo moss balls are basically indestructible as long as you don't let them sit in stagnant water or get too hot. I've even heard of people keeping them in jars with no filtration, though I wouldn't recommend it for long-term health.