The coral could have died from a lack of usable light due to time on the power compacts. Not sure though.
What all is left in your tank now? Is it possible to set up a quarantine tank or have someone hold the remaining fish for you?
Have you double checked your parameters or readings with another test kit?
The die off of coral could have caused a chain reaction that killed off the other coral - depends on what type of coral you were keeping. Aptasia may not be the single problem.
John
"Critics are men who watch a battle from a high place and then come down and shoot the survivors." Ernest Hemingway