Has Instant Ocean's magnesium level changed?

[The Grizz]

From what I was told a while back that the buckets of Reef Crystals is better then the boxes for there levels of Calcium & Mag. The boxes are more intended for store use but it seems they are starting to produce more boxes rather then the boxes, I personally think that it might be simply because the buckets are more expensive to produce & harder to get rid of.

I have not tested mine lately but I really should, when I do I will post my results.