Protein Skimmer Power Bar Failure Death Toll....

[Aquattro]

The thing with oxygen is not adding it, but removing CO2. any water surface movement should off gas the CO2 in the system, making the water absorb more O2. If the power heads were causing any type of water surface movement, you should have been fine. Lots of tanks run without a skimmer at all, and do just fine. Not sure what to look for, but I can't see this being from the skimmer turning off.