To hold heat and humidity, I mean... I need to go out of town for the day, two days into lockdown and I'll be gone for about 18 hours (forgot about that when I set the eggs. ). I'm not worried about the temperature- that stays pretty steady, but I'm worried about the humidity dropping while I'm away. (home made incubator made out of styrofoam, duct tape, and an aquarium). Keeping it in the 45-50% range has been pretty easy. I add water every 8-10hrs or so and thats because its getting close[/] to 45%... but, then, the relative humidity in the house has been steady, too. Knowing that a brick is effectively a big, heavy, porous, spongy rock- I'm wondering if that will work to hold the humidity steady until I get home? I'm thinking: heat it up to 100 degrees in the oven (so it doesnt lower the temp in the 'bator) and then set it in a dish with warm water the day before lockdown... then I'll have 3 solid days of monitoring and testing my theory before I leave. Has anyone ever done this?