I finally learned after too many times. I typically have to calibrate my refractometer a couple times when I'm mixing salt. I keep calibration fluid rubberbanded to it so I don't forget. It helps 90% of the time hahahaMine is dumb but also lazy — I got very lax on checking refractometer calibration. Long story short LPS and SPS corals began going south and I was pulling my hair out trying to figure out why. As a last effort at figuring out the cause I thought, oh, just to be thorough let me just check the calibration on this refractometer… Discovered I’d let my salinity dip to 1.020 sg
I did something similar moving rock around. Not sure where it ended up or if I blocked him in one of his caves or what but it was a bummer. Blennies are super cool fish with tons of personality. Just waiting to find the right one again!A long time ago I killed a wrasse that was in the sand. I thought that I had all of the fish out of the old tank and into the new tank. I drained all of the water out of the old tank and moved it to the garage to clean it "later". I didn't realize that I had not transferred it to the new display until it was too late. I still beat myself up over this.