You won't OD with Seachem Iron unless you seriously overdo it. The stuff is mostly water.
As for CSM+B, yes it has some copper in it. Many, many people with shrimp use it and don't lose shrimp because of it.
1. Watt [ wot ]: noun -- the SI unit of power, equivalent to one joule per second and equal to the power in a circuit in which a current of one ampere flows across a potential difference of one volt.
2. Per [ pur; unstressed per ]: preposition -- for each; for every.
3. Gallon [ gal-uhn ]: noun -- a common unit of capacity in English-speaking countries, equal to four quarts.
What does this have to do with growing plants?