I was wondering how Chronometer calculates the mineral content of supplements. When I enter 50mg of zinc citrate, it should reflect 17mg of zinc (because zinc citrate is 34% zinc), or about 200% of the RDA of 8-11mg of zinc.
But it seems to be showing 600%of the RDA, and of course the zinc: copper ratio is also off the chart. This might suggest that you are using the whole weight of the compound, instead of just the weight of the zinc, which would massively overstate the mineral intake. (Though the percentages vary, the effect would be the same for all mineral salts—calcium citrate is only 21% calcium and chromium picolinate is only 12% chromium).
Although you could embed these factors in your database, there could also be some value in allowing users to make the adjustment—or at least alerting them to the possible discrepancy.