In this thread post your most idiotic reefing mistake

[xenon]

About 6 years ago, I attempted to QT my fish with ich in hyposalinity (1.009).

I dropped them from 1.026 to 1.009 properly (3 points per hour).

I noticed the fish not doing very well once I got to 1.009 so I quickly added some salt to the water and they bounced back. The following day I got some proper calibration fluid and I was off my 3 points. What I thought was 1.009 was actually 1.006.

Lesson learned.