Alternate title: We're always just one step away from reef Armageddon. So -- my 120 gallon LPS tank crashed last week. I woke up in the morning to a tank that wasn't just cloudy -- it was nearly opaque. I'm detailing this so hopefully it will keep it from happening to someone else or if it does they can recognize the symptoms faster and minimize the issue. Here's what I observed that morning, Cloudy water, decaying reef smell, all the corals closed up (and I mean all of them), dead invertebrates littered the sand which was covered with grayish detritus. All of the Trochus snails and Turbos were dead. Strangely enough the Nassarius were mostly fine. Brittle stars (dozens of them littered the sand as well. About half the rock flower Nems were dead or missing. The two BTA's in the tank also dead. All three large leather corals were dead as well. The corals near the top of the tank were hit the hardest. Euphyllia at the top was dead, but those near the middle and bottom were closed up but still had some life. All of the fish were fine although a little less "perky" than usual. Test showed nitrates and phosphates were high (but not at a killing level). I attribute this to the die-off on inverts and corals. Alkalinity was at 10.3 although I keep it at 8.5-9.0. In an LPS tank it was doubtful that was the problem, but I considered it., Other things I considered and had recently changed/added. I had done a water change the night before. So I thought perhaps it was a bad batch of sale (IO), but I had used the same batch on another tanks water change as well so that was doubtful. I had put in two new bags of Chemipure, but a little research and experience pretty much ruled that out. The only significant change I had made was adding a titanium ground plug in. After a lot of research I came to the conclusion that a simple ground plug could not have been a factor. However, the reason I had added the ground plug was because for about 6 months I had noticed a little stray voltage in the tank. It wasn't effecting anything so I didn't really worry about. Again research -- a little stray voltage can be normal because of our equipment and a little bit doesn't effect corals. If it's too much some fish with a "sensitive' lateral line might show behavioral issues, but I hadn't seen anything at all for at least half a year. Besides -- I was sure I knew where it was coming from and it wasn't actually inside the tank. When I noticed stray voltage (a small tingling in my fingertips) I just moved the Kessil cords a touch and it went away. I have four Kessils' daisy chained together and assumed it was a connection issue, but since it seemingly wasn't in a cord in the water (just at the top rear of the tank) and because a little jiggling cured it I ignored it. Turns out I didn't delve deep enough into the issue even though (as Mike told me) usually stray voltage issues come from pumps or heaters -- you know the submerged stuff. I have regularly cleaned and maintained my pumps but regularly meant about once every 6-9 months because they are a bit of a pain in an AIO to reach and pull out (because of the cords.) After numerous water changes the tank cloudiness dissipated, but not all the way. Corals were still closed up a week later. One fish had dies. And so I grabbed a ladder and reached down to check the pumps. And a cord on the oldest of them completely separated with almost no force at all. Just a touch. Sure enough that cord was intertwined with the Kessil cords in the back and moving one moved the other. Lessons learned -- maintain the corded equipment much more often. Don't just assume the issue lays elsewhere. I ignored it because I was "sure" it was the Kessils and because it had been there so long but wasn't effecting anything. The tank was healthy and growing nicely. I added the titanium ground just to be safe even though I thought it wasn't really a tank issue. I should have delved further. So -- it wasn't a total crash. Over the next few weeks I'll have a better idea of losses, but this was not only a good learning opportunity, but also a good excuse to buy more corals.