fluffy white mold - cure?

[mexorchid]

I found my new baby cattleyas staying very wet around the roots and some roots turning black already. I slipped them out of the pot so they can dry better between waterings (the moss is so tight around them, that the package didn't fall apart but stayed the same shape so I left it like this). They sit on a grid on top of a water filled basin. I moved them inside an aquarium, top open for more humidity around leaves and added a weak light.

Not even 1 week later I see white fluffy stuff growing on their moss and their roots. I removed the aquarium immediately, not removed the water filled basin. I couldn't find physan20 in the shops here (if anybody knows of a shop in Quebec city, please let me know) I have read you can dip your plant in hydrogen peroxide (3%) - do you really mean dip the whole plant in the disinfectant????? It's not gonna harm the plant?

I'll also try to repot as soon as I can find some appropriate pots. I was thinking small clay pots and drilling some additional holes into the sides. Using again moss (they are small-medium seedlings) but very loose around the roots?

If you have any advice for me please post it!!! I'm really scared of killing them!