Wash the oranges, scrubbing well to remove any preservative wax on the skin. Peel off thin strips of rind from two oranges with a vegetable peeler, leaving the white pith behind. Chop peel into thin strips.

Peel the oranges and remove the white pith and tough membranes. Segment or finely chop the fruit. If segmenting the oranges, opt for seven oranges. If you choose to chop the oranges, six should be enough.

In a large saucepan, combine the chopped fruit, sliced peels, 3 cups water and 3 teaspoons calcium water. Bring to a boil, reduce heat and simmer (covered) for 20 minutes to soften the peels, stirring occasionally. Add 3 tablespoons lemon juice.

Mix 2 1/2 cups sugar and 3 teaspoons pectin powder in a separate bowl. Bring fruit mix back to a boil over high heat. Slowly add pectin-sugar mixture, stirring constantly. Continue to stir vigorously for 1-2 minutes to dissolve pectin.

Bring orange marmalade back to a full boil. Boil for one minute, and then remove from heat.

To can your orange marmalade, ladle quickly into prepared jars, filling to 1/4 inch of top. Wipe jar rims and threads. Cover with two piece canning lids.

Process jars for 10 minutes in a boiling water bath canner. When processing time is done, let rest a few minutes in the water bath, then place jars on a towel on the kitchen counter. Allow to cool completely at room temperature.

Remove rings for storage. Wipe tops and test seals. Date and label and store in a cool, dark location. Best if used within 1-2 years.

If any jars did not seal, refrigerate and use within a month.