I would not interpret the description of the Brightwell nanocode to mean it supplements trace elements.
" NanoCode A also provides non-conservative minor and trace elements
in natural seawater concentrations to help simplify the maintenance of inorganic water chemistry in nano-reef aquaria. "
The term natural seawater concentrations implies it is not a supplement, except as a very tiny water change each day would accomplish. To me that is exactly what a two part should do, and it does not supplement trace elements, but rather keeps the two part itself from depressing these ions due to salinity increases.
I know it may be confusing that it seems like a supplement containing, say, copper, must be supplementing it, but in fact, it may not do so. it could even lower it.
I discuss how that works here:
There is no aspect of reef aquarium chemistry more important than calcium and alkalinity. Many of my previous articles have described various aspects of these systems in detail. In reading those articles, aquarists will note one pervasive theme: that maintaining appropriate levels of each are...
www.reefedition.com
One issue that has confused some reef keepers, however, is the presence of trace elements. Assuming that these products are actually formulated with every ion such that a true natural seawater residue remained (let’s call this the “ideal” product), then it will necessarily contain such ions as copper. Since copper is elevated in some reef tanks, and is toxic to many invertebrates, reef keepers have wrongly criticized this method as adding more copper. That’s actually not what would happen. Since these products leave a natural seawater residue, and since copper may be elevated in concentration in many reef tanks relative to seawater, then using these “ideal” products will actually LOWER copper levels because when the increase in salinity is corrected, the copper will drop.
For example:
You have copper in your aquarium at 4 ppb and salinity of S=35.
You add a two part additive that over the course of a month raises salinity to S=36, and raises copper to 4.02 ppb.
Then you correct the salinity back to S=35 by diluting everything in the tank with fresh water, and you get a final copper concentration of 3.9 ppb.
Does this happen in real products and not “ideal” products? I have no idea. But the statement by manufacturers that it contains all ions in natural ratios, including copper, should not be viewed as a concern that it is exacerbating a heavy metal problem.
The rise in salinity of these products over time can be very roughly calculated, though there are several reasons why this calculation is only an estimate. For every 1000 meq of alkalinity added in this fashion (and the matching amount of calcium) these products will deliver on the order of 60 grams of other ions to the tank. In a tank with a low calcification demand (defined later to be 18.3 thousand meq of alkalinity per year in a 100 gallon tank (0.4 dKH/day)) this effect will raise the salinity by 3 ppt per year (compared to a normal salinity of S ~35). In a high demand tank (defined later to be 219 thousand meq of alkalinity per year in a 100 gallon tank (4.4 dKH/day)), the salinity will rise by 35 ppt in a year, or approximately doubling the salinity. Consequently, the salinity should be monitored closely in using these types of additives, especially in a tank with high calcification rates.
