We had blossom end rot five years running. Then we read about putting a single "tums" tablet with each plant when planted. This year we've had no blossom end rot. Seems to work.

Blossom-end rot is caused by calcium ion deficiency and very rapid ripening. Work dolomite into your soil before planting next year. This will give you both calcium and magnesium ions, needed for growth of many plants.