aguita,
A couple more questions to help drill down what happened.
1. Do all 3 ponds have HSB or just the ones with aeration?
2. What is the size of the other 2 ponds?
3. Are the HSB in the 2 other ponds the same age and size as the ones in the 3 acre pond?
4. Did the other 2 ponds freeze over completely with snow on top of the ice and stay as long as the 3 acre pond?
I did a search and found an article that might help you.
https://www.pondboss.com/news/moderators-corner/to-aerate-or-not___is-it-really-a-question
