Blossom end rot

[Phillip Armstr]

Who is able to give me some advice?

I am a new grower and have tried a small hydroponic trial.

I mostly have have Heirlooms in the hydroponics, and have picked up Blossom end rot. I have added Calcium Nitrate as well as Gypsum to my solution.

How long does it take before the fruit will not be affected by the calcium deficiency? A friend also has the same problem with his tomatoes in a tunnel, that are planted directly into the soil.

Thanks in advance