Just curious, why are you growing these in a terrarium? Oncs and Phals, especially the hybrids do just fine in normal house conditions.
As Ray says, their light requirements are different. If you were growing small plants in a terrarium, then it's possible to change the light they get by adjusting the plant's position.
As for high humidity, the majority of orchids deal with it fine, providing that there is good air circulation. Stagnant humidity is a killer. So a fan or two is a must.
Completely orchid obsessed and loving every minute of it....
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