Hydro + well water + leaf burn

Hello,
I am in the country and have hard well water. I have been struggling with leaf burn during week 2 of veg and week 1,2&3 inbetween the veins or in the "meat" of the leaf. I used R/O water for a while and that had it's own challenges. I am trying to ascertain whether it is a nutrient deficency or a poisining. It happens on the main shade leaves and starts with a yellowing and then burn and crispy death. I am at 1230PPM (weak) It almost starts looking like a Nitrogen deficency. This is an ongoing problem and I have had enough.
Any troubleshooters have any advice?

Rhinoman

is that 1230 EC x700 or EC x 500?
what EC does your water start at?

It sounds to me like you need reverse osmosis water. Your water sounds really hard. I start my plants out at about 300ppm EC x 500
I think you have nutrient lockout. It just seems like N deficiency.
I could be wrong. I have seen this problem before though.
In my opinion the water you start with is more important than any magic nutrient.

Fill-out the troubleshooting form, and likely we can stop this guessing game.

But in case you prefer the week(s) long process of answering one question at a time...does your EC probe have a ph meter built-in? (what's your tapwater ph?)