DIY Dosing

Hi,

I would like to make my own solutions for dosing calcium, iodine, magnesium molbenum, strontium etc. I teach science at high school and have access to all the stuff I need and I have search for recipies on how to make them. BUt...none of these recipies have any information about how much to dose.

I have some Kent Marine stuff and it is very specific on how much to dose, like 5 ml/50 gallons and then like once per week, daily, etc. But none of the DIY recipies has this information.

Kind of stumped at this point.

Thanks