Pond Boss Forums INTRO Questions & Observations Pond Bloom

I agree with ewest. Something has changed, and it might even be something that you can't see, like more dissolved fertilizer in the incoming water.

The denser the phytoplankton bloom, the higher risk you run of running low on O2 when the sun is absent, either very cloudy days or at night. Anything less than 12" visibility on a secchi disk would raise warning signs to me on making sure the aeration system was running during any period of clouds or at night. At night the lowest O2 levels happen right before sunrise, but I'd play it safe and start aerating when the sun goes down.

SOMETHING had to change recently, or you'd have had this problem way before this.