over time more of the liquid helium in the tanks turns to gas, but the temperature remains the same. just a quick message to say thank you for the plants – excellent quality and great service. i have moments of joy and mostly i’m kind of just smiling or looking at the snow covered trees out my window and it’s a good feeling but not anything i would consider to be like happy happy woohoo but that might just be me and my black heart made of coal. we will train 4th and 5th grade “student rangers” to help monitor organic waste disposal. 