glass lid

[myselfandme2]

Does a glass lid stop co2 from entering the aquarium?

 

[Fresh2o]

Typically, no. It would have to be almost sealed (allowing no air to pass).

 

[Mebbid]

Glass lids do a couple things to the aquarium.

1 - reflect large amounts of light away from tank

2 - Slow down the exchange of gasses (thereby reducing evaporation)

If you're not using co2 supplementation, it will likely cause a very slight increase in the amount of co2 in the tank (but not enough to make a difference for plants typically) through fish respiration.

If you are using co2 supplementation then you increase the risk of gassing your fish.