Help!! Should I cull?

Not sure what's going on here. Doesn't really look like a deficiency as they've been described and photographed around riu and other forums. Looks most like mosaic virus stuff or some kind of pest or something.
These are nirvana white rhino fem'd seeds germed in mini-hempy cups and grown out in mini-hempys until they started getting a mag. deficiency; when it was time to transplant i switched to an earthbox full of ffof. the girls loved it but the lights fell while i was cleaning and hit all the girls but a hot 2700K hit squarely on the one in question--should i cull her? she looks sickly, has dry brittle new growth that is yellow in the centers of the fan leaves. Sometimes on the new growth the leaves are so narrow it looks like barren stem halfway out the leaf towards the point. I'm not sure what's causing this and I'm worried its a disease or something spreading to one of the other two (healthy) girls...should i go ahead and cull the sickly one or see how it plays out--the problem has been present since a week before flowering and now its day 3 of flowering (wednesday will be decision day as to whether sick-girl stays or goes).
check out the pics:


these are for comparison and show where i think the problem may be spreading to a healthy plant:


Edit: Here's a link to my journal for a complete case history: https://www.rollitup.org/blogs/299352-dr-j20.html

She should recover if the damage was only physical.

I think you need to take a close look at your pH levels.

Snow Crash said:

She should recover if the damage was only physical.

I think you need to take a close look at your pH levels.

Click to expand...

Thanks for the response...not sure if its physical damage but i checked the pH with a soil tester and its lookin like 7.4-7.5 after a few measurements so i guess i need to drop that pH...whats the least stressful way to drop pH i guess should be my next question...thanks a bunch snow,
be easy,
Dr.J

Mix up 2 gallons of 6.5 pH water for every gallon of media.

You can use Lemon Juice to drop the pH of your tap water if you do not have access to pH down.

Run this through the media. The concept here is a gentle change over time. This rinsing should get your media down around 7.0, which is acceptable for the time. Continued feedings with 6.5 pH solution will gradually bring the pH down over time until you balance out. Just be sure to get plenty of run off every time you water for at least the next 3 weeks.

Yeah i've got ph Up and Down from when they were in hempys and i will definitely be doing this adjustment slowly over time...you think Lemon juice is safer or better than ph Down?

Enh, I dunno... Probably not that big a deal. I'm sure if lemon juice was some secret to fat buds we'd all know about it by now. Either way will be fine I think.