Rockwool Vegging Plants Leaf

[merkaba]

So, I just noticed this odd spotting on my leaves. The plants are healthy and growing but are starting to show these leaves. I am thinking it's a ph or maybe I am not prepping my rockwool correctly? 6" HUGO blocks, soaked for a few minutes in 5.5ph solution of House & Garden Aqua Flakes under T5s. I hand water as needed, though I am thinking they might do better with a drip system in veg.

 

[vostok]

Look close and you may see the veins of the leaf still green whilst many of the centrel leaf 'panel' are burnt, I'd go with Mg def, and apply 1/4 teaspoon of Epsom Salts to a pint hand sprayer and spray morn and night for 7 days, or 1 tsp per gallon and water, greening will start at the top and work down in 10 days