Another Moorish Idol bites the dust

[Aquattro]

No, temp is fine. It's 78-79, which gives me better growth on the coral. O2 levels that Sam and I are talking about are not in that 3% range you mentioned.
Dosing just before lights on is probably not an issue, and with most fish in a tank not heavily stocked, likely not really an issue after lights out. Could be, but not likely, depending on load.