I'm hoping to hear from people who have technical knowledge regarding the negative effects of using an almost-sealed glass cover on top of a freshwater aquarium. I have heard things such as increased water temperatures and gasses being trapped, but I would like to hear about these issues in more detail.
Greatly appreciate your comments.
Well, in my own experience I use a glass lid on my tank.
Temperature is usually the same as room temperature, maybe 1 or 2 degrees F higher (so 70-72F on average). I do not use a heater, since the species I keep do not require one, if that matters. I use LED lights, they generate little heat.
Not sure about gases being trapped, what kind of gasses? I keep african clawed frogs in my glass lid aquarium and they breathe oxygen and I've had no issues with that. I do open the lid once a day for feeding so I don't know if that helps. I did cut the plastic to allow me run to place the intake and spray bar, I've cut it very tightly to not allow much of a gap to allow escapes (my frogs are sadly, awesome at escaping).
The tank also has a small population of ghost shrimp, whom I believe are very oxygen sensitive? Besides the shrimp my clawed frogs eat, I've never seen one die from issues with the water chemistry due to a lack of oxygen. My tank is planted, though so that may help with oxygen.
I do think that glass lids do keep water from evaporating, so that's good. It does appear to trap humidity in, if you have plants that grow out of the water such as I do again another positive.
Also keeps your fish from jumping out (or in my case, frogs), so again a positive.
