Yes- moisture got to the batch and broke down many of the elements contaminating the batch
lol
I don't mean to be critical of you, since they said it, but this is a science forum and I try to ensure things are actually correct if I read them here.
An element is something like H (hydrogen) or Na (sodium) or Cl (chlorine) or Ca (calcium). With the exception of radioactive elements in the batch (of which there certainly are some tiny amounts, such as carbon 14 in the bicarbonate that slowly converts into nitrogen). No normal elements are ever transformed into other elements.
When moisture enters a salt mix, the main things that happen are:
1. Some salt dissolves into tiny water droplets in the mix, and they can then reprecipitate, linking grains together and clumping the mix. This is no concern and the mix is still good, but might get hard as a rock.
2. There is some dissolution of calcium chloride (maybe also magnesuum chloride and/or sulfate) and sodium carbonate/bicarbonate into tiny droplets of moisture. That allows formation of calcium/magnesium carbonate. That material will not dissolve when you try to use the salt mix, and lower alk in the settled mix is the indicator that this has happened.
I discuss the precipitates in salt mixes here:
What is that Precipitate in My Reef Aquarium? by Randy Holmes-Farley - Reefkeeping.com
from it:
Figure 1. The residue on the bottom of the plastic trash can that I use to mix Instant Ocean. I rarely clean it out. The solid is most likely calcium carbonate.
Solid Residues Remaining After Preparing Artificial Seawater
Most salt mixes leave behind a solid residue when dissolved, although the extent to which this occurs varies from brand to brand. I use Instant Ocean and rarely clean out the 44-gallon trashcan that I mix it in, so a significant residue builds up over time (Figure 1). In preparation for this article I removed some of this solid material, and found that it could be almost completely dissolved in hydrochloric acid with lots of bubbling. This demonstrates that these solids were probably calcium carbonate (CaCO3), perhaps also containing
magnesium. Pure magnesium carbonate is undersaturated in seawater (which is detailed in later sections of this article)
1 and should dissolve in marine systems, so it isn't likely to be the precipitated material, although there may be significant magnesium in the calcium carbonate.
Based on the fact that the material exists as sheets that clearly did not arrive in the mix (as opposed to a fine powder which might have), I conclude that at least a significant fraction of this residue formed in the barrel. I cannot, however, rule out the possibility that some solid calcium or magnesium carbonate may have existed in the salt mix and was cemented together by additional precipitation of calcium carbonate during dissolution or storage.
When salt mixes are dissolved, there exist local regions where the salt concentration is very high. In those local regions, the
calcium and
alkalinity must also be very high. In fact, as seawater is concentrated by evaporation, there is a well-established series of minerals that precipitate as the salinity increases. In this series, calcium and magnesium carbonate are the first to precipitate, appearing at a specific gravity of about 1.140, which is about a 50% solution of salt in water.
1 Such conditions may well exist on the bottom of a saltwater reservoir as the salt is dissolving.
With some mixes (but not the Instant Ocean that I use), the
initial pH on dissolution may be very high (pH 8.5-9 +). As shown in detail later in this article, pH can play a dominant role in determining the rate of calcium carbonate precipitation, and such a high pH would make it more likely to precipitate.
It has been suggested by some aquarists that some salt mixes may contain anti-caking agents, such as clays. I do not know if this is true, but if it is, they may form part of the residue that is left behind after dissolution.
In order to minimize the formation of insoluble carbonate salts when mixing, the following suggestions may be helpful:
1. Add the salt to a full batch of water, rather than adding water slowly to a large batch of salt. The latter allows a greater time at much higher than natural seawater salinity, which may tend to precipitate calcium and magnesium salts.
2. Stir the mixture vigorously as it is being dissolved.
3. If using a mix with a high initial pH, aerate the mixture as well as stirring it. The aeration will reduce the pH.
Havent used anyting but Frtiz the whole time. It must be a conspiracy! I have corals going for over 20 years and somehow with all my naive ignorance...... Lolz The best part is they made the salt because they are hobbiest's, who happen to run one of the biggest salt mixing companys for industry, and had access to pharma grade product to make a "perfect salt" so I thank them for it , and so far its the best ive seen or used outa all of the brands available for us and our coral. They need this part of the bussiness like a hole in the head. 
