Small leaves, purple leaf stem and veins. Newer growth drooping

Thanks guys! I may put my tube heater outside the tent where air is being sucked in as it may be getting cold at night. And I'll let her dry out and give her a flush with ph water as I've got a feeling it may be ph again. P defficiency crossed my mind... but lower leaves seem to be fine l. Any thoughts on that anyone ? What would you say is the best ph for early flowering ?

What medium are you growing in? Do you check the pH of your water after adding nutrients? It should be around 6.5 for soil. The soil might be too wet too often, or the light could be hanging too close, or maybe cold air is being drawn into the tent. There can be various causes. But that doesn't necessarily mean it's a disaster for the further growth of your plant. I've had that with my plants too, and I’ve now adjusted my pH and raised my light a bit, and I've been letting the pots dry out properly more often, and the plants are now in week 10 and I think they’re doing great.

Lamp to plant distance can certainly cause purple stems and veins, as well as bleaching of leaves closest to the lights, yellowing tips, burnt curling leaves. Having the light 13 inches away is pretty close for early flower. I run a spider farmer sf-1000, and during early flower I have to be about 22 inches away or I start seeing light damage. Other than that, make sure your ph is where it should be, and don't water until the top inch of soil is dry. Happy growing.