How much ventilation?

[Pumpkin]

I'd like to improve my glass tank setup a bit--I'm looking at switching from a UTH/lamp combo (with thermostat and dimmer) to two UTHs (and two thermostats) because my humidity is just a little lower than I'd like in between misting. I've heard covering the screen lid can do the trick, but how much ventilation do I need to offer? Are we talking a few holes or a pretty good amount?

Thanks

[Regius_049]

I don't know that there is an exact right answer here, but if I were doing it, I would leave maybe a 1" strip of the screen open on both ends of the cage. This will allow natural air flow from one side of the cage to the other.

Something like this, but with one opening at each end -

[Pumpkin]

Thanks--that's about like what I was thinking of doing, but I wasn't too sure.

[Yzmasmom]

I just have the area just around the lamps open. Not much open area, but it's enough to get air.

[melcvt00]

I have my lamp directly on the metal screen, and the foil completely covers the top except for about a half inch around the lamp.

[Albert Clark]

Thanks--that's about like what I was thinking of doing, but I wasn't too sure.

. Another consideration for you and your setup will be to purchase a "versa top". Folding glass top with a plastic attachment that can fit various gallon sized aquariums. Sold at Petland, Petco, and Petsmart. Humidity issue solved and ambient temperatures improved.

[Pumpkin]

Thanks everyone--I really appreciate the input!
I was interested in those glass "versa top" ones, but I didn't know if that would provide enough ventilation--also unsure as to how the lid locks would work with it.