[David]

Hi Ken,

I use glass to cover the top. Some users use acrylic. You can actually buy a fish tank in an aquarium shop these days with acrylic or glas cover already built in. That would save you the trouble of buying and cutting a piece of glass and figuring out how to support it on top of the tank.

If your terrarium is covered with only a small gap, you should not have mosquito larva in the water in the tank. Also If you wash the tank regularly, maybe once every 2 weeks or so that would wash away any mosquito larva. So far I have not problems with mosquito larva in the water cathment area in my Terrarium and I am quite lazy to wash my terrarium. So the there is always water there for a long time.

As for air circulation, I use an aquarium air pump.