Yellow spots on tips of leaves ?

Ok I got 4 ladies under 600 w hps first week of flowering the rest of my plants are doing great but there is one that seems to have brown spots outlined in yellow on the tips of the leaves it seems to be only on the new growth.

I've been feeding ff nutes for veg and will be continuing the ff nutes for blooming this coming week or so they are in sunshine #4 mix with perlite and ffof

Temps 77
2 co2 boots buddy's

Will have pics up soon

Here's some pics

what's the growing mediums pH?
IMO- you have a iron deficiency showing on a few leaves.
That is usually caused by other factors, soil pH, soil water, soil temp. or toxicity from another nutrient will lock out other nutrients, and show a deficiency.

Good Luck on Your Grow

Try feeding some epsom salt. It should improve and won't hurt anything.