Hey AB
Your plants are looking bushy and happy. 450ppm seems pretty reasonable for early Veg.
I've just set-up my replacement Flower Tent and instead of 2 x 600W HPS and 2 x LED's , I've gone with 4 x LED's for Summer. Actually, I've still got to order the 4th LED. I've got 3 x Meizhi's with real pulls of 405W. Last Grow I had a Viparspectra and liked it. So I'm thinking of doing another Vipar to run a side-by-side comparison.
Can I ask you something? With your perpetual situation, how's your power bill? Mine, even with solar panels, was over $700. I assume electricity costs the same in the West as the East!