12V fan questions
 

It seems like some people are using the 3 1/8 Coralife fan, which i am afraid might be a bit too big for my 18 x 18 x 27 orchidarium (both visually and air movement wise).
Perhaps 1 fan like this might just do the job?
Would I need two fans to get thorough air circulation?
Could I get a voltage adjuster to slow this fan down?

I was also thinking of going with 2 smaller fans I think...
I've found some smaller 40mm and 50mm 12 volt fans.
My question is what are people using for their ac/dc adapter/converters?
Are any of these adjustable?

Hi! I use the coralife fans, in particular the size you mentioned and the next size up. The smaller size is in my converted exo-terra about the same size as yours....in my opinion...it's not enough! I've even pulled out the black mesh thingy to help increase the amount of air flow. I have two of this size...one sits on the floor and one mounted on the ceiling...I would really like one of the larger sized coralife fans to replace it eventually. Hope this helps some!

Yeh, I agree with Becca. I use three of these in my tank which is about twice the size of yours. With all of them, I removed the filters to improve air flow. Two are completely inside the tank recirculating the air and the third is on an end wall pulling air through the tank. I also have misting nozzles assuring humidity stays high. I think you are fine with one fan if you take off the decorative mesh piece from the front. If you need a second one, you can always add it. The 4" model is much louder than two of the 3" fans would be.

My father is an electrical engineer who likes to tinker. He ordered two 120 volt "muffin" type computer fans and rigged then in sequence rather than parallel. They are incredibly quiet that way, and blow a gentle breeze. Now I wouldn't actually know how to do this since I've always relied on my dad, but it's an idea that has worked well for me.