Welcome to the OB.
Please correct me if I'm mistaken, but I take it you've never grown an orchid before, so we'll start from the very beginning.
1. You have what are called Moth Orchids or orchids in the genus Phalaenopsis.
2. The 2 plants you own are man-made hybrids.
3. If the plants did not have name tags, they do not have a name that designates what cultivar it is. Therefore it will be considered a NOID (no ID).
4. NOID's are difficult to pinpoint a name to because there are many man-made hybrids that have been produced that look very similar to one another.
In regards to root health...
The following links are examples of what healthy Phalaenopsis roots look like:
http://www.aboutorchids.com/blog/wp-...oots_640px.jpg
http://www.gardenworldimages.com/Ima...OTLECOUFLE.jpg
With the photos of healthy Phalaenopsis roots in the links in mind, do know that by comparison, your plants have damaged root systems. It is salvageable though.
To give you an idea of how Phals grow, these following links are examples of species Phalaenopsis growing in the wild:
http://www.ibanorum.netfirms.com/Lundu-orchid190207.jpg
http://lh6.ggpht.com/_F4h2El7hQQo/S8...na4%5B3%5D.jpg
There are tons of information on the OB regarding the cultivation of Phalaenopsis. If you have the time to sit down in front of the computer and browse through the plethora of posts about how to grow them, you can do a search on the OB search engine.
As far as your lighting is concerned, it may not be adequate. Lighting is a complicated matter to be talking about, so I encourage you to do your research regarding lighting.
Without having to cover the basics of the complex nature of lighting physics, the short version is...
I would shoot for Power Compacts that are as long as the tank is long, with a Kelvin rating of 6500 K. The Home Depot has some of these for sale, along with the fixtures and ballasts. However, it is a diy situation.
The Exo-Terra tank is fine.
Make sure the plants are not sitting in water.
If I may ask...
What are the sizes of the pots they are currently potted in?
What is the potting media they are currently potted in?
What are the day and night temperatures they are being subjected to currently?
I recommend a humidity of roughly 60% - 70%. If it's 50%, it's okay.
If you have other questions, please don't hesitate to ask.