I think you should try pumping more air through. I'd be concerned, though, that the high humidity will wreck your light fittings. Maybe you could put a piece of clear stuff between the lights and the plants, and run separate air through that tunnel? I wouldn't worry about losing UV if you use acrylic.

/me goes off to find out what effects UV has on plants.

Thanks so much for the response! Hmm, Dad is an electrical engineer so I'll ask him about the possiblity of water hurting the fixtures...I sent him your reply so that he can mull it over :) Any other advice or suggestions will be appreciated as well.
Amy

I don't think increasing the amount of air through an orchidarium is a good thing. For one, it dessicates and you must supply continual humidity to replace what is vented outside. I think the best option is to relocate the ballasts outside of the orchidarium. It's a very simple process and all that heat can be outside of your case, rather than in it.

This way, you might be able to find some level of homeostasis in your case without needing to supply loads and loads of moisture from a humidifier. It will save on mass amounts of electricity, too-and with 6 fixtures and 4 or 5 fans, any saving helps.

Sam

Generally more fans are the solution to high heat, but since you already have a fan that is interfering with your humidity, I wouldn't advise it. If the ballasts aren't already outside the tank, I would move them, as Sam suggested. Since your dad is an electrical engineer, he probably used waterproof fixtures, knowing about the humidity, but it he didn't, I'm pretty sure it's easy to switch. More expensive, but you can't have electrical fires or electrocutions happening! I would definitely relocate those top lights outside of the case though, and make the top glass. Glass is cheaper than plexi, won't ever warp from any heat the lights put out, won't yellow over time, is easier to clean without scratching it, and don't worry about your plants not getting UV rays! My lights on my terrarium are outside, with glass in between, and my plants grow just great. My orchids flower and everything! I don't think plants need UV rays. In fact, it's probably UV rays that cause leaf burn, just like they cause sunburn in humans. BTW, what kind of lights are you using? They look like standard shop lights, though they do appear to be cool white, which is good. How many bulbs are there on each level? what is the wattage?

COncerning the lights being inside the case if not waterproofed, I don't think the situation is that important is certain precautions are taken.

1- The outlet you plug your orchidarium MUST be(and should be even if waterproofed units are used), GFCI. GFCI outlets will trip an internal breaker if a ground fault is detected. A ground fault is basically whenever there is a major short in the wiring.

2- All internal connections must be sealed up with either liquid electrical tape, or some other form of insulation.

3- The ends of the lamps where the contacts slip into the fixture need to be covered in something that will protect against corrosion. Most electrical supply places will have products you can use for this that will protect against shorting as well as protect the electrical surfaces.

4- Be damned careful about spilled water! But I'm sure you already knew this one :-]

I'm sure your dad did take some of these precautions and he no doubt is aware of methods and products to protect wiring as well as yourself.

Sam

Reread my post - I think my suggestion addresses all the concerns, and it will be cheaper than replacing everything.

Insert a new piece of acrylic between the existing lights and the plant shelves:
---shelf--- f
a
--acrylic-- n

that way the heat is vented out the side, but doesn't interfere with the humidity.

Oh, good idea, we hadn't considered that yet. I have sent all these suggestions on to dad for him to mull over, thanks again everyone! You know much more about this than I.
Amy