Gentle Readers,
Sometimes the Old WaterKeeper goofs and he did in his most recent article on lighting. CalforniaDreamer pointed out to me that the H in HQI stood for Hydrargyrum (Latin for liquid silver and the alchemists name for Mercury (Hg). I have been calling them High Quartz Iodide for years and, upon checking, found out Dreamer was indeed correct. I guess the lamp manufactures thought that too many people would feel they were mercury vapor lamps if they used that term so someone switched it to high in their advertising. The gullible WK took the bait and has been miscalling them for years.
Thank Dreamer for giving me the straight name.
Tanya,
Corals don't shed polyps and if they do they are dead and don't grow back. "Shedding" is a term used more often for the mucus film formed on corals to slip off. The film is used for food gathering, reproduction or protection from a hostile environment and it doesn't harm the coral to shed it.