Joe Yaiullo, one of the pioneers of reef keeping in the USA, and the curator/co-founder of Atlantis Marine World in NY has been feeding NLS (daily) in his reef tanks for the past 10 years. You can view his 20,000 gallon reef set up (the largest in NA, and 4th largest in the world) in the link below, where he also mentions feeding New Life Spectrum.
http://www.advancedaquarist.com/2007/2/aquarium
Joe is one of the world’s most highly regarded Aquarium authorities. He has consulted with many public Aquariums worldwide, and has also presented reef-keeping lectures throughout the United States, Canada, and Europe.
Bob Fenner, who is widely known through his various published works on aquatics, as well as his wetwebmedia website, has stated that New Life Spectrum is a nutritionally complete food, to the point of it being the best food, period.
http://wetwebmedia.com/foodsppt1.htm
Bob's bio can be found here:
http://www.wetwebmedia.com/WWMAdminS...ex/bobfbio.htm
Charles Delbeek M.Sc., senior biologist at the Steinhart Aquarium in San Francisco also feeds NLS at their facility. You can view Mr. Delbeek's bio in the following link.
http://www.jcdaquariumdesign.com/Pages/about_us.html
The gentlemen mentioned above are not only highly respected, very experienced long term reef keepers, they also hold one or more degrees in the various related sciences, and would most certainly never use
anything in their systems that even had the
potential to harm any type of life form.
Also, none of those individuals have any type of vested interest in New Life.
FYI - the form of copper used in all NLS formulas is copper proteinate, some of the older labels may show copper sulfate, but that form of copper hasn't been used for a couple of years or so. It's simply a case of older labels being used up instead of throwing out several thousand $$$ worth of labels. Not that it mattered either way with regards to this discussion (both forms are a non-issue at these levels), just thought I should point that out.
Also, please keep in mind that almost
everything and
anything can become toxic at high enough levels, including some vitamins. No nutritionist would recommend completely eliminating vitamin A, B, D, E and K from the diet just because at higher levels these substances can be toxic to a fish, yet this exact type of logic is what's used when some hobbyists discuss
essential trace elements such as copper.
HTH