I recently finished an ytong nest that I was proud of and tried to test it to see if humidification system works correctly before putting my colony in it.
The problem appeared after approximately a week from starting the test. The nest is built to have a a water reservoir from which the ytong to absorb water and keep the nest moist. I add water in the reservoir and the ytong absorbs water as needed. I intended this nest to be smart and to be able to remove the requirement of adding water each day. Partially it worked, but somehow after a week a section of the upper part of the nest that was wet, molded and I don't know why.
The mold is pure white, a little bit similar to cotton.
Here are some picture linked to have a better understanding and look of the mold:
I must mention that last year I built a similar nest and the same problem happened. At that time I thought that maybe I touched the ytong with something that eventually molded. This time I made sure this is not the case. If anyone can tell me what went wrong, or why did this happen, please let me know. I'm starting to believe ytong is not the best way for a nest, at least for me, and think on going back to building it out of plaster of paris. With plaster of paris I never had this problem.
Long live the queens!