Blossom End Rot Application

[TomatoDon]

I know this is old hat to practically everyone here, but I like to review the crop at year's end and see what I learned. This year my main problem was deer and coons, which is a totally different topic.

For now, I'd like to get an idea of what the growers here used to prevent blossom end rot. I know it has to do with water uptake, or lack thereof, etc. but I want to see what commercial products were used on a larger scale for blossom end rot. Such as, liquid through a drip line or dry amendments in the planting hole, or as a later side dressing, foliar spray, etc.

I know about the egg shells and tums and even Epsom salts (which I am becoming wary of) on a small scale, so I'm interested to learn what people use who grow a lot of tomatoes, such as 100, 500, 1,000 and more. I want to see if there are any new commercial products that can be bought in bulk other than the ones most of us have used in the past. I remember that Algo-Flash used to have a good line of products and one I used was called Cal-Mag, which seemed to work well.
Thanks
Don