Hi Redwhite! Welcome to ATP!
Terrariums can be a bit difficult to get "balanced." And I agree with everything Lin has said, in particular about the soil... I use Miracle Gro potting soil for starting seeds and had a really strange white mold stuff this year that has never shown up before. The first step I would take is opening your terrarium up to the air for a good while... and yes, you may just need to start over, sad to say
; save what you can and replant.
