humidity & light - need advice please!

[mexorchid]

Happy for a bit of advice on my baby cattleyas! Any suggestion is very much appreciated!!!

I got them a bit over a month ago (from Cloudorchids and they all looked very healthy and good size). Under my unexperienced care I felt they are not getting enough humidity but too much water at the roots. So now they are on their usual grid over a water filled basin (the water is warmed a bit with an aquarium heater) but I slid them out of their pot (and really I found some roots turning black already). The moss is so tightly packed around their roots that it's not falling off anyway. And I put the whole basin inside an aquarium. Do you think that will get humidity up a bit? Any tips? Do I need already a fan if the aquarium is open on top?

Also I found a light with an aquarium plant bulb, 15W. It's the black, hanging "bar". The window is north/west and is only having very little direct light in the late afternoon. With the winter coming I feel there is not enough light any more (Quebec City).The orchids are different Cattleyas and 2 mexican orchids (NoID). Do you think the light will burn them? Is it hanging too low (between 40-55cm over the plants)? How long per day should I keep it on?

Thanks in advanced for your input!