So I planted my usual tomatoes this year.  I planted the cherry tomatoes in an Earthbox and then the full size tomatoes is a regular pot.  Again, this year the cherry tomatoes developed blossom end rot.  I lost the first 8-10 tomatoes.  I googled it to see what I needed to do.  After the first several articles I was pretty convinced my tomatoes weren't getting enough calcium.  The articles suggested things/chemicals to buy to solve the problem but I was too lazy to go out and buy something so I smashed up two of my calcium vitamins and dropped them down the watering shoot and in two days I was picking perfect tasty tomatoes.  Problem solved!