Is this a Zinc deficiency? How do I treat?

Hi there,

I'm 5 weeks into a long veg on a Indica dominant bagseed. I'm in Bio Bizz all-mix soil with bat guano and dolomite lime mixed in, I haven't been checking the pH as I've been using dolomite so I reckon I might have locked out Zinc. I was, possibly incorrectly, told that I wouldn't have to check the pH of my feedings whilst using dolomite as it keeps the pH of my soil at 6.5 no matter what I water at.

Just to be sure an hour ago I flushed the plant with water at ph 6.5.

Please have a look at these images below and let me know what you think,
many thanks!
Razz

Forgot to add that this started happening after I xpanted it into a bigger pot. the light is 60cm (24") from the top of the plants. It's a 600w dualspec HPS in a cooltube