i had a crash and a half.
two summers ago i went to Atlantic City for 4 days, and left the tank in the care of my cousin, who was suppose to take care of top off and keep the tank cool by turning on the AC and fans, if needed (summers in north jersey can get hot). well on the last day he forgot, and when i arrive the tank was at 91F. EVERYTHING, but one hermit, one false percula clown (who's still with me today) and one green chromis (also still with me) was killed. the nutrient release was so massive that it took 3 months for the tank to recover
the half crash was entirely my fault. this happened about two months ago. for some reason the pH got very low, but i was out of my normal stuff, so i bought something new since it was the only thing i could find at the time. being fearful, i only used 1/4 the recommended dose, and planned to add an additional dose the following day. well the stuff never really dissolve, even in a jar of RO water, but i figured this wouldnt be too serious. my mistake. the fine powder i suspect irritated my corals, and it ended up killing about 6 specimens, including a bunch of pom-pom xenia. the algae blooms are just about under control now, and everything appears to be back in order
I learned my lessons, and hope never to repeat my blunders