I've never used BioBizz, so I don't know their dilutions...but they look like either they are a tad starved, or they were starved.
If it started after the transplant, I'd make a little adjustment. Either I'd increase the nutrient dosage a little tiny bit, or soak the media a bit more when giving nutes. If it started before the transplant, I'd give it a few days to see if there is any improvement in her growth.

Often, old leaves are old news, and there's nothing that can be done to improve the appearance of a necrotic leaf. Work on keeping the new growth happy. :thumbsup:

You mention the runoff at 6.7 but didn't mention the tap ph. Also...does the tapwater smell like chlorine, and do you use a micronute additive or Superthrive?

20 inches is a bit far for a 600w bulb, isn't it? Can you get it closer without burning the ladies?

Perlite and vermiculite are basically benign, (harmless) unless it dries-out the soil too quickly.