2 or 1 Lightning

Depends on efficacy. Assuming that is the same, you may get better distribution of light with 2 lights vs 1. But, the differences will be small as long as they are all the same efficacy. The best way to plan for this stuff is to use the umol/s of PAR listed for the light -- assuming it is accurate. More than a few manufcaturers fib quite a bit about this stuff. I can say the mars FC series are accurately rated, but not as familiar with the other stuff. So, you want a light that gives you 576 umol/s, give or take 5% -- or combination of two light that adds up to that is fine too. Two TS1000's at 85% over 12 hours would be a good place to start. 56% power in 18/6 cycle vege or autoflowers. Having too much isn't so bad in this context. Likely save a few watts per umol/s PAR produced (improved efficacy). Running the diodes at 85% will also increase longevity of the diode. As they age, you can amp up the power a bit. The 50k hours before tehy hit 90% of original intensity only applies to the highest efficacy lights. It will be a bit faster than advertised, but at 85% would extend that a bit (ie the increased longevity mentioned). You could also cover 117% of your current space at full power from 2 of these lights. -- 1.17 * .64 = .75m^2 -- with context of 12 hour operation. Could do autoflowers (18 hours) and cover 1m^2, give or take a bit. ---------------------------- How i got there: Work backward from the area of coverage -- and assume typical 18-24" hanging distance -possibly a couple inches closer even. At some point getting closer without damage only reudces light penetration (inverse square law applies to how light spread out over incremental distances) .64m^2 18 hours target of 600 PPFD for 38.9 DLI 600 * .64 = 384 umol/s of PAR needed -- distribution of diodes being important too. 12 hours target of 900 PPFD for 38.9 DLI 900 * .64 = 576 umol/s of PAR needed. 576 / 300watts = 1.92umol/J -- so this is verry low requirement. THat's about what an HPS efficacy is. Even a shitty LED will be 2.2umol/J. 576 / 2.2 = 262 watts of a low-end LED. or 576 / 2.8 = 206 watts of a high efficacy light. At this size, 60watts per hour saved isn't going to be noticeable. It may takes 4-5 years to gain back the extra cost of the light in this size-range. Simple break even math with your average per kw-hour cost of electricity. So, you want a light that gives you 576 umol/s, give or take 5% -- or combination of two light that adds up to that is fine too. --------------- About TS1000 PPE 2.3μmol/j PPF 343μmol/S That looks fairly reasonable. They aren't over-promising, so i'd expect these are close enough. two at 100% would be overkill with 686 umol/s. you'd want to run them at 84-85%. This would exctually improve your efficacy a bit (at diode, possibly hurt a bit at driver, but 85% load should be fine for most drivers - full load for drivers is usually most efficient for that equipment). In vege for 18/6 you'd need 2/3rds of that -- 56% All from normal hanging distances. This would require some trial and error to dial in exactly how much you can give without damaging the plant. This is a ~39 DLI target. Depending on temps, rh and most importantly atmospheric CO2, your mileage may vary.