Sounds like they've come a long way since the old days of the 400 & 600w poots I grew up using, they used to buzz like an electricity substation and the ballasts got really hot! Excellent that you can dim yours too, ideal for those very hot spells in the summer 👍🌞
Yes, I had to dim it in mid to late summer to keep temps close to 25C. Also added a cooltube mid summer to help with the heat. Had the odd day creep up to 28 but usually between 22 and 25 lights on. I still have a 400W HPS magnetic ballast. I use it if a plant needs a bit more veg before going in the tent. It doesnt get too hot though but definitely much warmer than the digital ballast and yes it hums a bit.
Base nutes are DNF Bloom A&B. Used DNF grow A&B throughout veg. Vegged about 4 weeks then flipped to 13/11 and been running that schedule ever since.
Started using monster bloom at 21 days then every 10 days or so. Introduced DNF Gold to regular feeding last week and a shot of Cal Mag here and there when I noticed some leaves with brown spots.