It seems to me the 4500 is running much hotter at 95% than 2 2000 @ 60%. 2 2000’s @ 60% is also higher ppfd than the 4500 @ 95%.
Interesting about the heat. The driver for the 4500 is removable, right?
I see the set up in the first picture. It looks like the lights and the plants are really close to the same size. I think I see what's going on (helps to look closely).
Re. temps - latest research data is to the temp of the tops of the buds <=78° to minimize loss of secondary metabolites. Check out the "Crop steering" video on YouTube by Mitch Westmoreland. It's about 50 minutes and it's a superb summary of some of the work he did for his PhD.
I am considering a 3rd sf-2000 for the next run which i will put in a 3x3.
You've got a good handle on lighting. Good to see. There are a lot of lights for the 2' x 4' and 4' x 4' but the 3' lights don't have the PPFD values or PPFD maps as do the other tent sizes. Dunno why but if you look at Spider, Mars, Migro (cough, cough), etc. that form factor just isn't up to the others. Your approach to "DIY" makes a lot of sense.
It is hard to compare the two side by side cuz the 4500 is over a mimosa i brought from outside seeds from a survival kit.
The 2 SF are above growers choice seeds and there is a clear difference in genetics.
Interesting that you're seeing that. My understanding is that indicas and sativas have different light saturation points. Is that what you were seeing?
The co2 is natural but drops off as the day goes on right now my CO2 is 550. I don’t supplement.
Got it. That's "human generated"! Heh, it all counts. Even at 550, you're getting a bump.
I was running 1200 ish ppfd for a few weeks but thiught i saw some burn damage. I think i may turn it back up again for the last 10 days of flower.
1200 in ambient is pretty high but you've got more CO2 than average so things should go fine as long as you're vigilant.
How are you measuring PPFD?
If you've got some photos and would like an opinion, I'm more than happy to give an opinion.

I will say that you're doing things right if you're dealing with light at the 1k mark. Well done.
I grow in a 2' x 4' and use a variety of lights over the course of a grow and the highest I've run is 1150. My EC was, arguably, a bit low at 1.8 but once you go over 1kµmol, that's "playing above the rim".
If you do raise PPFD again, you'll want to revisit VPD and EC. With additional light coming in, the plant is generating more glucose ("food") so it will probably benefit from additional fertilizer ("vitamins and minerals") and the increased VPD will increase transpiration. Transpiration is how plants cool off but it also accounts for 90%, by mass, of nutrient uptake. For a lot of growers it doesn't "click" that all of those factors function in concert. I spent a few days with chatGPT refining my growing processes and that's when I learned that my EC was probably too low.
Re. VPD - just a reminder to measure leaf temperature offset as part of your VPD calculations. Fans blowing from underneath the plants can dramatically drop leaf temps, a good thing as long as it's done in moderation, of course.
The main light is a Growcraft X3 flower light with Spider Farmer Glow R80's to up the red %. The Mars SP 3000 (2020 model) is on a clothing rack because the colas on the front row of the plant were quite a bit lower than the center and back of the plant. The Mars was only at ~60 watts but it was enough to even things out. Off to the right is a little Vipar XS 1500 for the small plant on the right side of the tent.
A big issue is not just the PPFD in flower but it's vital to ramp PPFD ASAP/starting with day 1. I get my grows to 1k by about day 35 but cannabis can use that much light at the 3-4 week mark, assuming that the grow environment is sound. In my case, I haven't been giving my plants enough nutrients so they've taken a bit longer than optimal. If you're keen on getting the most from your plants, lots of light as early as possible is the ticket. Not that I have an opinion on that, of course!
