Nitrogen, Underwatered, or Lights?

[bulba]

Hey guys I've been growing 3 Blue Dream plants in 3 gallon fabric pots inside a 2x2 grow tent under ViperSpectra XS1000 grow lights. 1 of the 3 plants has some leaves turning yellow, but it's not exactly at the bottom, more like in the lower middle. The last time I watered them was 5 days ago and the soil was pretty dry that day, I gave them each half a gallon with half a tsp of CalMag in the 6.0-6.5PH range. The soil is dry again for 2 out of 3 plants (3rd is getting there) so I was about to water them with just PHd water until I saw the yellow leaves so I'm not sure if I should add some Nitrogen. I have had the Fox Farms trio in my closet but haven't used anything except water and CalMag (previously had a calcium deficiency problem before flipping to flower a month ago). So my question is should I add Nitrogen now? Should I increase the water from half a gallon to 1 gallon per plant? I thought of the possibility that the lights aren't reaching but the other plants seem fine. This is my first grow so I've been really cautious and didn't want to give it the wrong solution.

P.S. I swear I got a whiff of blue dream!

 

[ProPheT 216]

She looks fine. Those leaves could be old mistakes. If you mess up you'll see those leaves die off early from that time period.

 

[bulba]

She looks fine. Those leaves could be old mistakes. If you mess up you'll see those leaves die off early from that time period.

Thanks for the input! Last week they weren't yellow and I removed any that were with the assumption that they were just older leaves. Also you can't see it too well but one of the yellow leaves on the back side is a big fan leaf and I thought it was too soon for that one to turn yellow. I take them out of the tent to water and appreciate them (as cheesy as that sounds lol) so that's why I know none were yellow when I put that back in last time. So you think I should be good then?

 

[ProPheT 216]

It doesn't look like she's feeding off of the lower leaves..watch for it to spread. it just looks like the older leaves are dieing from a past mistake when she was young to me. U could do a slurry test and check what's going on in your medium as far as ph and ec

 

[bulba]

It doesn't look like she's feeding off of the lower leaves..watch for it to spread. it just looks like the older leaves are dieing from a past mistake when she was young to me. U could do a slurry test and check what's going on in your medium as far as ph and ec

Thank you! I appreciate the information, looks like I'll be giving them just water as planned this time around.