Dart Den

I recently built a vivarium, it has an excellent drainage system... It has a waterfall made out of cypress drift wood, After 5 days of running it before inserting many plants I noticed a white fuzzy mildew on the top of my co-co hut as well as a bit on a section of the waterfall where there isnt running water. I have the circulation within the tank very limited so as to keep the humidity high, is this mildew a problem? or how can I fix it?

mold is common in freshly setup tanks and will go away as things stabilze.