White tipped sun leaves ?

Hey all,

So, I'm growing in soil (pH 6-7) under flourescent tubes and I've got white edges on the leaves. I looked around here, but the only thing similar I could find was either a phosphorus (or magnesium?) deficiency, but that starts from the veins and works outward.
This is starting on the edges and progressing inward toward the veins.

Humidity is around 60-65% and temps are about 70-75. It's not light or burning because the plants beside it are fine. It's on this one plant at the moment but I think it might be starting on another. This pic is a couple days old and it's now affecting all the new leaves on top of the plant.

Any thoughts ?

nute burn?

Could be early calcium def.

Thanks guys, reps are out.

This one isn't getting much for nutes at the moment, so I'm inclined to think that it's lacking something rather than having an excess of something.

I checked out calcium defiency and, from the description here it sounds like it could indeed be low calcium except that it seems to be happening more on the older leaves than the new growth. Chlorosis and tip (though not margin/edge) necrosis seem to be there.

This is what she looks like at the moment:

Man they look like they're made of paper and were colored in with a crayon.

Potassium deficiency. Give them a nice high-K guano tea. GL

Hehe - yeah, I was thinking they looked airbrushed and they do have kind of a papery feel to 'em.

I'll head to the garden center today and see what I can find to give it a shot of K.

Thx dood.

So...this is the potassium supplement I picked up. I looked for guano, but the only stuff they had was for phosphorus rather than potassium.
I gave it a dose last night so tonight I'll post a pic if there's any improvement
This stuff reeks so it must be good !!