[Hairytank]

Thank you for the messages.

My guess is on a temperature spike as well. It can get pretty warm if the windows are not opened at night for a short while when it is hot out. Another problem was the protein skimmer fell "off-line" (plugged air intake) while gone...my bad, but was working while I was here.. The algae was not horrendous or anything and the Po4 was not overly high (<0.25) so I am sure while contributing this was not the sole culprit..

I have a Tunze ATO and it was working well, so the SG was bang on.

There was an acro looking a little washed out before I left due to some lower dkh levels, but was colouring up nicely when I had dosed and brought levels up (slowly) before leaving.

After looking at things, it is likely a heat spike knocked off a couple of the weaker corals and then overwhelmed the tank with the corals dying off and it continued throughout the week.

Unfortunatley, my fishsitter was simply not in a position to recognize the problem or that there was a problem , which is my fault not his..

More lessons to be learned the hard way.