It is recommended for individuals aged 50 and older to aim for a total of 1200mg of calcium per day. Taking 500mg of calcium as a supplement, your diet should provide you with around 700mg of calcium. It is important to calculate your calcium intake before adding more supplements, as consuming too much calcium can have negative effects on your health. As for magnesium, getting a blood test to measure your levels is the best way to determine if you are deficient. Additionally, taking too much magnesium can lead to diarrhea. It is important to be mindful of your intake of both calcium and magnesium to ensure you are meeting your body's needs without causing any harm.