White marks on cork forest background..

[Heatheranne]

If it's calcium deposits it's not a problem.

[JHansson514]

Lately I've had the same white spots in my tank as well, but I don't have a waterfall. It all started when I added a fake plant that has a wood base and it definitely started growing mold. I took the decoration out immediately, but a few days later I noticed the white spots on the substrate. I have also noticed the same spots on potted plants outside the tank (just like Pandora) with the same substrate as the tank (I intended on putting these plants in my frog tank, I was just giving the root system a head start). They almost look like a version of snow mold, the stuff that is sometimes on the grass after winter. I think I would lean more towards the spots being mold, but I agree with Heather that hard water definitely causes calcium deposits, but it takes a few weeks for it to be visible. Unfortunately I don't know how it affects frogs, but I assume it can't be good.