Regards
After the summer I will build a 5x5 space and plan to put a Mars Hydro FCE 8000 in it which is 800w.
Now I have a 4x4 space and 600w hps. Considering that curent grow will end late in June, I will almost certainly have problems with temperatures.
The question is whether I can use the fce8000 in a 4x4 space. According to the dimensions it fits, but I don’t know if it will be too much.
You can see from the post that I don’t understand LED, dimming… so any comments are welcome
Thanks
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Yes but you should dimming it to 400-600w.
As more you dimme your leds so more effective they will bE and less heat produce
Try out how much light your plants want, there are many factors who decide how much a plant can take.
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There will be a dimming knob on the driver for your Mars light. Run it at 50%-75% in the 4x4.
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Hey @Pannonian I have my FC-6500 in a 4x4 and it’s a light cannon. If you do this with the FCE-8000 you’re never gonna need to dial it up all the way.
I don’t see this as a problem personally. If you really wanna dial things in perfectly get an app based PPFD meter online (around $100-150 vs $300+) so you can know your levels based on the knob turns.
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No such thing! Lol
Just turn 'er down. 
If it physically fits, I’d say that you’re good.
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It’s ok. With HPS/MH you don’t want to dim as it messes with the spectrum or at least that is what I have read. With LED, you can dim away. I have an FC 8000 and dim it rather than move it. Costs a bit more in hydro but I don’t have to raise the lights as the grow progresses.
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I like how you think, wall to wall diodes, I have a hlg 600 rspec in a mars hydro oversized 3x3, I’ll max out at 60%because of the heat produced.
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This is a great point to bring up @Cory !
My FC 6500’s ballast is OUTSIDE the tent for 2 reasons. One is to keep the heat down, and the second is I can put my PPFD meter inside the tent and then close up the door to then see the trve light levels taking in account the reflective light from the door.
Door open/closed sometimes showed a major diff in light levels, expecially in full flower.
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Ok.
Thanks everyone
The important thing is that it can be used.
Then it’s up to me. To play with the height and dimming and determine the most even coverage in the desired ranges.
And thanks for future answers 
I need help
I just put a Fce 8000 which is 800w in a 4x4 space
I downloaded the Photon app, and the readings are very different from the numbers listed on the Mars Hydro website.
If anyone can give me an approximate height and percentage of power, and that I’m on the safe side. I’ll find a solution tomorrow
It’s pretty late here and I need to water the plants, and I get up extremely early in the morning. It wouldn’t be a good idea to waste time with the light either.
Thanks
LED ignoramus
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Did you pay for the ‘full spectrum’ led option? What kind of paper are you using for a diffuser. I think it’s supposed to be #22.
Don’t have any input on distance and dimming. Sorry. That’s a big ass light in a tent.
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Im not sure for diffuser. And it should be full spectrum
I will put on 50% and 14 inch above plants.
According data from coco for cannabis 12 inch hight is about 620 ppfd
Thanks and
Good night
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For photone you need to pay the $8 or whatever it is and use a piece of standard paper as a diffuser.
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Hopefully this helps 
Idk about 50% for seedling that seems a bit high to me ¯_(ツ)_/¯
Not really comparing apples to apples I’ve never used that light, in a 4x4 tent I use a HLG600 r-spec and will do seedlings @20% n gradually increase % over time and go by rec height
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