Below is a pic of my enclosure. I'm about 6-8 degrees short of my target temp using heat tape on the top back screen. Enclosure is 12x12x18H. I have a piece of 1/8" thick Plexiglas taped down above the screen to help trap in the humidity that I need. I was thinking of using a UTH and sticking it to the Plexiglas to increase my heat. Using a thermostat of course. I have this enclosure in a tight spot since it's front opening and not much room above it to mount lighting so I'm using a thin LED strip. So that won't at any heat.
Think using a UTH on top would work?
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