It's terrible to think that all that hard work, time and money invested in your reef tank can be undone by a 40$ piece of equipment.
So far all my coral, inverts, fish and my clam look good.
The most depressing things I tell new people.. One of them is my outlook on the inevitability of a tank, the other is my personal feelings towards livestock. Both grim, but with a purpose.
1) One day you will wake up, and your whole tank will be dead. It's almost an inevitability, something will fail, a heater may crack.. Just recently a friend of mine had a UV Sterilizer crack and melt ABS into his tank. This guy has well over 20 years experience and a very nice system. He never would have guessed that was the cause. One day he went to check on it after MONTHS of everything dying and poof, black tar on his hands (melted ABS). Nobody would have guessed. Not me. Not him. Not our friends. Not our club, with probably a combined 200 years of reefing experience!
2) Your tank WANTS to die. Every animal you have wants to go explore the carpet. Every coral wants to sting each other to death, or melt away for no reason. It's our job to play detective and keep that from happening, with jump screens for fish, safety tops for overflows, clean water, coral placement, trace supplementation, etc etc etc.
This can at first seem like a very bleak outlook... But really having this mindset does two things... Soften the blow, and prepare you for the uphill battle that is keeping a saltwater reef. And you can have success for MANY years, for it all to suddenly crash one night when you're asleep, or on one vacation. I'm not saying this to scare people. I'm saying this to get them prepared, and ready to act without panicking.
Slow is smooth, and smooth is fast. Panic is reckless, reckless is slow.
Lastly, my two favorite sayings that pertain to reefing (and one from fishing)
1) Only bad things happen quickly.
2) If you think you're fishing (reefing) slow enough, SLOW DOWN.
If you keep those two mindsets and sayings in the back of your mind, you can solve ANY problem you run into. The only other thing one needs besides some mental adjustment is a few pieces of backup gear... A cheap "just in case" return pump, a flow pump, a few heaters. Cheap ones are fine for emergency.