There is a saying out there that a chain is only as strong as its weakest link. In literal terms, this means the strength of a chain is limited to that of the weakest link in the chain, even if other links are stronger.
I believe reef keepers should take this saying to heart. There are many things that can cause a reef tank to take a nosedive and spiral out of control. A return pump could seize up, a needle valve on a C02 tank feeding a calcium reactor could malfunction and dump excess C02 into the tank, a dosing line could get clogged, and so on.
Have a Solid Plan in Place
Many of these things can be prevented with regular maintenance but sometimes misfortune can be caused by poor planning or a faulty design when setting up equipment.
For instance, I have a float switch in my sump that is designed to kill my auto top-off when the water hits a certain level in my sump. The problem is this float switch is positioned too high in my sump so by the time it is tripped my salinity will plummet. MORE
reef aquarium, sps frags