What deficiency is this?

A question from a fellow grower:

Quick question…is this a calcium deficiency or another deficiency of some kind ??
It’s off the middle to a bit higher of 3 different plants…

Light source CFL’s ? Heat issues ? if nutrient issues all leaves would present it - Nutrient splash ?

Are the leaves stems purple? most of the leaves look like contact burns from splash but some show signs of mag def.

i think my plant might have what you have my stem is purple Bottom leaves died, had some root rot and mineral build up, changed the water and added some root starter Looks like new roots are out but leaves keep dying

I switched from Aerogarden(shitty system) to a 5 gal dwc with only 2.5 gals of wateralso switched from cfl to mars reflector 48 150 watts with 2 100 watt cfl, its been 3 weeks since transplant

What are you using for nutes? and are you adding a Cal-Mag supplement?
Magnesium def would most likely be your culprit since it is more readily absorbed in higher ph. Let your ph fluctuate between 5.5-6 if you add Cal-mag set ph 5.8-6 will absorb and clear up most of the issue though be easy on any feeding during root recovery think like its a fresh cutting. Carob molasses may also do the trick if you don’t have Cal-mag supplement
http://www.marijuanapassion.com/forum/attachment.php?attachmentid=112496&stc=1&d=1241462952.

Keep in mind ph of 6 would speed ability to absorb but 5.8 will work too if you don’t want to risk overnight ph climb

Yes botanicare cal-mag