I've done some investigating. We had a party on Saturday night, and every time I went near the laundry room, the door was closed. I kept opening it, but the last time I checked was about midnight. There's indigo stains all over the inside of the wall and door, right at butt height, so you can imagine why the door kept getting closed...
We have a massive server stack in there that powers the home automation and distributed audio/video system for the house. We know it puts out a lot of heat, which is why for the last 7 months the door to the laundry room has never been closed. While I was doing a complete reset to the QT system today, I closed the door to see how hot it would get. After 2 hours it was 30 degrees in there. I've done every test I can think of on the water they were in, but I don't have a max/min thermometer. My best guess is that the water got too hot and the dissolved O2 fell below levels anything could survive in. The tank had too many fish for it's size already, so I doubt there was a wide margin of error for oxygen. It's either that, or a drunk party guest decided the fish needed a drink. Pretty brutal considering how close they were to going back in to the main tank. Between the failed hypo treatment in the sump and then the QT system, I've had them 'in treatment' since August. That much time and effort blown to pieces less than two weeks away from the finish line.
Does anyone know if a tank crash like this will also damage the bacteria bed in a canister filter? I tried to save it by running it in an empty salt bucket with water from the nuked system, and today I cleaned the tank and all the equipment and re-filled it with 100% new salt water. The canister filter is back attached to the QT tank now, so I dosed it with enough ammonium chloride to hit 1.5ppm this afternoon to both keep the bacteria alive, but also to test whether it's going to go through a cycle again. After 6 hours the level of ammonia doesn't seem to have fallen any. I'm not sure if that means my filter is toast or not.
I'm going to be out of town more than I'm in for the next 4 weeks, so I won't be getting any new fish for a while, but I'm going to try and see this as an opportunity to do this whole thing again properly. I'm going to add fish slowly, and only after a rigorous prophylactic treatment of copper. All new corals are going to be quarantined in the new cadlights all-in-one nano tank I just bought to make sure that not a single drop of outside, potentially contaminated water will make it in to my system. It's not going to be easy, but I am going to try my hardest to make my system pathogen free going forward.
I'm also going to take this time to try and deal with my growing aiptasia problem using berghia. I'm pretty sure the reason I never had success with them in my last tank was that a) I let the problem get so out of hand the nudibranch's couldn't make a dent in their short lifespans and b) I had tried peppermint shrimp first (which didn't work) and I'm pretty sure the shrimp were eating both the nudis and their eggs and c) I had wrasses that I'm pretty sure were also eating the berghia. Since my tank is going to be fishless now for at least 6 more weeks (groan!), I may as well try berghia again as there's nothing in that tank that could eat them, and the problem isn't so bad they couldn't clear it out.
Other than that I'm actually blown away at how well the display is doing. Now that the algae is gone, corals that seemed like they were in stasis are bursting to life. Frags that hadn't grown an inch in months are sending out base plates at a rate I didn't think was possible. I had no idea how inhibiting algae could be to coral growth. I tried taking some top down photos tonight when the lights were on their way to being super blue, and man, I just can't figure out how to make the LEDs jive with my iPhone. The photos look nothing at all like it does in real life, it's like the sensor only sees the blue, and then captures is as horribly as possible. I tried adjusting the white balance in photoshop afterwards, and this was the best I could do:
This coral came to me completely browned out, with only the tiniest hint of blue at the tips. It's probably changed the most out of all my corals. This pic is as close to how it looks in real life as I could get with photoshop.
