New Life Spectrum fish food and copper

[midgetwaiter]

Originally Posted by Myka

I like the math. Although I'm sure it's safe to assume that daily exposure to copper would be damaging at a lower level than 0.4 ppm.

Well you're right about that but again inputs due to food are basically irrelevant.

Shimek found pretty significant impact on urchin larvae at .01ppm , issues with coral fertilization at 0.014 ppm and reduced feeding by nassarius snails at .05ppm

If we pick this level where invert or coral larvae are affected (.01ppm) we have a problem. Referring to the AWT salt study again we can see that there is only one salt (Kent) that has an average concentration of copper below our target when freshly mixed. All of the others are between .02ppm and .03ppm. One of the Kent samples was at .01ppm but the other dragged down the average.

What do we pick as a target if our salt mixes are already too high in the first place? Do we disregard the harm done to the most delicate larval life stages and pick an arbitrary level?

Originally Posted by zoaElite

Are any of you chemists that have done studies on the effect of "Copper sulfate" or any other copper compounds on our reefs for that matter? If not, please stop accusing NLS (and every other company that has a copper compound in there ingredient list) of trying to kill our reefs, because that's just plain ridiculous.

Copper sulfate is a bad example because that is the compound found in most copper treatments designed to be toxic to inverts. Copper bound to some sort of organic molecule is probably not toxic so your point is well taken.

I was bored and decided to poke around for more information on this and what I found will hopefully kill this discussion.

http://reefkeeping.com/issues/2003-0...ture/index.php

Tables two and three in this article list the copper concentrations found in some commonly used foods, here's some highlights:

Formula One 2.3ppm
Formula Two 1.8ppm
Brine Shrimp 1.3ppm
Plankton 10ppm
Nori 3.0ppm

Unfortunately NLS wasn't analyzed but let's face it there is a certain amount of copper in everything we add to our aquariums. It's not an issue specific to NLS at all.