Richard Harker has been a reef hobbyist for 14 years. His first reef tank was a 90 gallon tank with primarily soft corals. The tank evolved into a stony coral tank in the early 1990s and he has primarily maintained small polyp stony corals since then. In 1995 he stepped up to a 300 gallon reef tank. Photos of the tank have been featured in numerous hobbyist magazine articles and is included in Mike Paletta’s new book, "Reef tanks of the world." In 1999, Harker built a 2000 gallon tank that features nearly 100 square feet of stony corals. The reef tank has been the subject of an article in the 2000 Marine Fish and Reef Annual and the German reef keeping magazine, Koralle.

Harker has published hobbyist oriented articles in several magazines over the past five years. In addition, he is the Product Review columnist for Advanced Aquarist. He has spoken at numerous hobbyist meetings including MACNA and the Western Marine Conference.

In addition to maintaining a large reef tank, Harker has explored natural coral reefs around the world. He has studied and photographed coral reefs on Australia’s Great Barrier Reef, Fiji, Solomon Islands, Papua New Guinea, The Philippines, Palau, Micronesia, as well as Florida and throughout the Caribbean.

ABSTRACT: Relationships Between Coral Growth and Spectral Quality

Back in the mid 1990s the question that generated some of most spirited debates (and flame wars) was, "what’s the best metal halide bulb for my reef tank?" Today we have far more data on metal halide bulbs then we had then. We now have detailed and quite precise spectral and intensity data on virtually all bulbs available to hobbyists, and yet today the question that generates the most spirited debate remains the same: "what’s the best metal halide bulb for my reef tank?"

The reason the debate continues is that no connection has been drawn between the published data and its relationship with coral health. Knowing the spectral quality of a metal halide bulb tells us nothing about how corals will respond to being lighted by the lamp. In this first of its kind presentation, I will present data on the response of corals to different metal halide bulbs and the relationship between coral growth and spectral quality.