My previous full tank shot.
On Tuesday morning at 3am my girlfriend took the dog out and noticed the outside sump overflowing. She woke me up and I can downstairs to find the tank a cloud with only about 6" visibility. The bottom of the tank was lined with dead tangs.
I went outside and found the sumps overflowing. My topoff had stuck on and added Kalkwasser to the tank for 7 hours. I have a double float switch, one measures the sump low, and a second measures if the water level goes to high. The switches are mounted inside a Black PVC pipe so that no snails and no algae can grow on them. Both switches coincidentally failed at the same time.
I did a 350g water change at 3am. The next morning the tank had almost zero visibility and the house smelled of dead fish. There were a scattering of carcasses in the tank. I had about 120 fish when the accident hit. There were still some clowns and Bangai cardinals moving about the tank. I did a 400g water change and added 5lbs of carbon.
While changing the water I was surprised to find 5 baby Bangai surviving in my outdoor rock sump.
Then after the water change I found another younger clutch of 3 Baby Bangai in the display tank.
Some of the fish which survived have surprised me. So far the survivors are 5 clowns, 5 Bangai, Orange Spotted Blenny, Mandarin Goby, Target Mandarin, Tail Spot Blenny, Several Firefish, Red Sea Regal, Blue Hippo, Chevron Tang, Dragon faced pipefish, a couple of damsels, Red Sea Regal and Multicolor angel. There may be more but the tank visibility has only reached the point where you could see the back of the tank today.
Fish loss between the display tank and the outside tanks is about 130 fish.
All the acros in the display tank are gone (about 126 pcs). The Montis are a mix there is about 50% tissue loss on them so far.
My LPS seem to be surviving but as a precaution I moved them to a friends tank for a week or so.
Zoa and Palys are a mixed some are open and some are closed and some are wilted.
I do have an Apex, and it was busy emailing me in the middle of the night but I was asleep.
Lessons I learned. My Apex topoff was programmed for the float switches, now it is also programmed to shut off based on Salinity and pH.
Hopefully things will continue to clear up and in a couple of weeks I can start rebuilding. The girlfriend has decided that Hannukah gifts to each other this year is going to be limited to fish and corals... What a great girl!