Never seen this before, what is it??

Under the lights i thought it was ca def at first but after getting it in plain light it is not.. I have not seen this in my plants before... what is it??


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Have you foliar fed anything? Checked for mites?
What strain? What cycle, Veg yeah?

looks like the start of a cal-mag def

Punctate rust spots beginning around the middle, upper middle of the plant was how I first saw Ca/Mg deficiency. I started using Botanicare's Cal/Mag with Fe and I'm very happy with it. Plants look great so you caught this very, very early, good job.

Feed it some Cal-Mag

That was my first thought too but it didn't use like the usual ca or mg i've seen before. They haven't been foliar fed, and last watering was just water + ej catalyst... oh, i also bumped up co2 ppm from 1000 to 1500 a few days ago in preparation for flowering so maybe bumping up the co2 has led to the plant not having enough ca to keep up with extra growth. It was also low on water even though I watered a few days ago... it may be approaching outgrowing it's pot (I use root stimulators every watering). I haven't given'em ca-mg lately either... luckily I always have ca-mg handy, and already mixed up 4 gallons of it -- also topdressing with some dirt with kelp meal, guano and lime pellets mixed in won't help much today but will help keep things in check for the next few weeks at least... this one'll be getting transplanted tomorrow as well so that'll help too.