First time grower trying to identify problem

Hi all,

Started my first grow with Coco Coir and have been following Dr. Coco's Cannabis feeding schedule and have started to run into problem with my Blue Dreams photoperiod.
I have identified from the last two feedings between my two plants that they are both getting nitrogen toxicity so I'm going cut my some micro in the next feeding.
However, between how this plant has reacted to nutrients versus my Northern Lights are very different.
My Blue Dream, as pictured has developed splotching after the first week and going on week 3 now and it has very slightly corrected itself.
Leading up to the problem may have been pH issues being too high during my initial week of feeding but I have since then corrected pH levels. Now I'm trying to decide whether it is an iron deficiency because of the splotchiness or something else.
I would appreciate if someone has point me into the right direction with this. Thank you!

I heard somewhere on here that the yellowing in the veins is from either calmag or iron deficiency. Hopefully someone more knowledgeable chimes in soon for you.

This is where growing in soil is so much easier. You can run several strains in the same soil and they will all be pretty happy. If some look hungry, feed them a little. With hydro you have to figure out exact nutrient demands for each strain. This is where commercial guys running 20,000 watt flower rooms filled with clones all from the same mother have everything "dialed in" and know exactly what and when to feed each strain.

To me it looks like three possibilities. 1. Nitrogen 2. Magnesium 3. Iron

Davmalk said:

To me it looks like three possibilities. 1. Nitrogen 2. Magnesium 3. Iron

Click to expand...

I wasn't entirely sure if I had a magnesium issue either.
Maybe what's throwing me off is that the new growth appears to have an onset of nitrogen toxicity, whereas the older growth appears to have a deficiency and possibly permanent damage from it. I'm unsure though!
I feel that an iron deficiency is large part of the problem and am suspecting I may have a lockout from improperly ph'ing the water during the early stages. Debating on doing a ph'd flush with RO water.