Even as a seasoned reefer, sometimes I make stupid mistakes that could have easily been prevented.
Example, last night I did a water change on my quarantine tank, but didn't measure the temp (did measure the salinity though) . Doing a 40% water change with 90 degree water is apparently bad, haha. Because I forgot to take the temp, it cost me about $700, as my baby Naso, male eightline flasher, and Mitratus butterfly as died last night.
Somehow (luckily) the most delicate fish in the QT, a Jewel leopard wrasse was fine.
What mistakes have you made like this?
Example, last night I did a water change on my quarantine tank, but didn't measure the temp (did measure the salinity though) . Doing a 40% water change with 90 degree water is apparently bad, haha. Because I forgot to take the temp, it cost me about $700, as my baby Naso, male eightline flasher, and Mitratus butterfly as died last night.
Somehow (luckily) the most delicate fish in the QT, a Jewel leopard wrasse was fine.
What mistakes have you made like this?

I added cold water when I first started, it made the fish lethargic, but fortunately no deaths. Another thing to look out for is adding a non reef safe fish to a reef tank, or an agressive fish. I saw an undulated trigger for 25 bucks, and would have taken it myself if I was a begginer, and did not know.

