Fish Tank Ornamets For A Large Tank Is The Water In My Fish Tank Evaporating Fast?

Is the water in my fish tank evaporating fast? - fish tank ornamets for a large tank

I have a 30 liter tank. During the night, about 1 liter of water (or more) has disappeared from the tank. I thought it might evaporate, but much like the night. I have a position of the fish from wood only lasts until the edges of the container is not the media and compatible with an empty space about 3 cm from the bottom of the glass of the aquarium. I thought maybe it s water leak in this cavity and is not immune against the floor. If the bottom of the tank? Is it necessary to raise the temperature of the water to prevent evaporation?